---
_id: '50287'
author:
- first_name: Stephan
full_name: Kruse, Stephan
id: '38254'
last_name: Kruse
- first_name: Tobias
full_name: Schwabe, Tobias
id: '39217'
last_name: Schwabe
- first_name: Pascal
full_name: Kneuper, Pascal
id: '47367'
last_name: Kneuper
- first_name: Heiko G.
full_name: Kurz, Heiko G.
last_name: Kurz
- first_name: March-Michael
full_name: Meinecke, March-Michael
last_name: Meinecke
- first_name: Christoph
full_name: Scheytt, Christoph
id: '37144'
last_name: Scheytt
orcid: '0000-0002-5950-6618 '
citation:
ama: 'Kruse S, Schwabe T, Kneuper P, Kurz HG, Meinecke M-M, Scheytt C. Analysis
and Simulation of a Photonic Multiband FMCW Radar Sensor System using Nyquist
Pulses. In: German Microwave Conference (GeMiC) . ; 2024. doi:10.23919/GeMiC59120.2024.10485320'
apa: Kruse, S., Schwabe, T., Kneuper, P., Kurz, H. G., Meinecke, M.-M., & Scheytt,
C. (2024). Analysis and Simulation of a Photonic Multiband FMCW Radar Sensor System
using Nyquist Pulses. German Microwave Conference (GeMiC) . https://doi.org/10.23919/GeMiC59120.2024.10485320
bibtex: '@inproceedings{Kruse_Schwabe_Kneuper_Kurz_Meinecke_Scheytt_2024, place={Duisburg},
title={Analysis and Simulation of a Photonic Multiband FMCW Radar Sensor System
using Nyquist Pulses}, DOI={10.23919/GeMiC59120.2024.10485320},
booktitle={German Microwave Conference (GeMiC) }, author={Kruse, Stephan and Schwabe,
Tobias and Kneuper, Pascal and Kurz, Heiko G. and Meinecke, March-Michael and
Scheytt, Christoph}, year={2024} }'
chicago: Kruse, Stephan, Tobias Schwabe, Pascal Kneuper, Heiko G. Kurz, March-Michael
Meinecke, and Christoph Scheytt. “Analysis and Simulation of a Photonic Multiband
FMCW Radar Sensor System Using Nyquist Pulses.” In German Microwave Conference
(GeMiC) . Duisburg, 2024. https://doi.org/10.23919/GeMiC59120.2024.10485320.
ieee: 'S. Kruse, T. Schwabe, P. Kneuper, H. G. Kurz, M.-M. Meinecke, and C. Scheytt,
“Analysis and Simulation of a Photonic Multiband FMCW Radar Sensor System using
Nyquist Pulses,” 2024, doi: 10.23919/GeMiC59120.2024.10485320.'
mla: Kruse, Stephan, et al. “Analysis and Simulation of a Photonic Multiband FMCW
Radar Sensor System Using Nyquist Pulses.” German Microwave Conference (GeMiC)
, 2024, doi:10.23919/GeMiC59120.2024.10485320.
short: 'S. Kruse, T. Schwabe, P. Kneuper, H.G. Kurz, M.-M. Meinecke, C. Scheytt,
in: German Microwave Conference (GeMiC) , Duisburg, 2024.'
conference:
end_date: 2024.03.13
start_date: 2024.03.11
date_created: 2024-01-09T08:12:04Z
date_updated: 2025-02-25T06:08:18Z
department:
- _id: '58'
- _id: '623'
doi: 10.23919/GeMiC59120.2024.10485320
language:
- iso: eng
place: Duisburg
publication: 'German Microwave Conference (GeMiC) '
status: public
title: Analysis and Simulation of a Photonic Multiband FMCW Radar Sensor System using
Nyquist Pulses
type: conference
user_id: '38254'
year: '2024'
...
---
_id: '54785'
author:
- first_name: Stephan
full_name: Kruse, Stephan
id: '38254'
last_name: Kruse
- first_name: Tobias
full_name: Schwabe, Tobias
id: '39217'
last_name: Schwabe
- first_name: Pascal
full_name: Kneuper, Pascal
id: '47367'
last_name: Kneuper
- first_name: J. Christoph
full_name: Scheytt, J. Christoph
id: '37144'
last_name: Scheytt
orcid: '0000-0002-5950-6618 '
citation:
ama: 'Kruse S, Schwabe T, Kneuper P, Scheytt JC. A Photonic Multiband Radar Transmitter
Architecture with Tailored Nonlinear Transmission Line. In: INTERNATIONAL CONFERENCE
RADAR 2024. ; 2024.'
apa: Kruse, S., Schwabe, T., Kneuper, P., & Scheytt, J. C. (2024). A Photonic
Multiband Radar Transmitter Architecture with Tailored Nonlinear Transmission
Line. INTERNATIONAL CONFERENCE RADAR 2024. INTERNATIONAL CONFERENCE RADAR
2024, RENNES.
bibtex: '@inproceedings{Kruse_Schwabe_Kneuper_Scheytt_2024, title={A Photonic Multiband
Radar Transmitter Architecture with Tailored Nonlinear Transmission Line}, booktitle={INTERNATIONAL
CONFERENCE RADAR 2024}, author={Kruse, Stephan and Schwabe, Tobias and Kneuper,
Pascal and Scheytt, J. Christoph}, year={2024} }'
chicago: Kruse, Stephan, Tobias Schwabe, Pascal Kneuper, and J. Christoph Scheytt.
“A Photonic Multiband Radar Transmitter Architecture with Tailored Nonlinear Transmission
Line.” In INTERNATIONAL CONFERENCE RADAR 2024, 2024.
ieee: S. Kruse, T. Schwabe, P. Kneuper, and J. C. Scheytt, “A Photonic Multiband
Radar Transmitter Architecture with Tailored Nonlinear Transmission Line,” presented
at the INTERNATIONAL CONFERENCE RADAR 2024, RENNES, 2024.
mla: Kruse, Stephan, et al. “A Photonic Multiband Radar Transmitter Architecture
with Tailored Nonlinear Transmission Line.” INTERNATIONAL CONFERENCE RADAR
2024, 2024.
short: 'S. Kruse, T. Schwabe, P. Kneuper, J.C. Scheytt, in: INTERNATIONAL CONFERENCE
RADAR 2024, 2024.'
conference:
end_date: 2024-10-25
location: RENNES
name: INTERNATIONAL CONFERENCE RADAR 2024
start_date: 2024-10-21
date_created: 2024-06-17T10:08:17Z
date_updated: 2025-02-25T06:06:04Z
department:
- _id: '58'
- _id: '623'
language:
- iso: eng
publication: INTERNATIONAL CONFERENCE RADAR 2024
status: public
title: A Photonic Multiband Radar Transmitter Architecture with Tailored Nonlinear
Transmission Line
type: conference
user_id: '38254'
year: '2024'
...
---
_id: '53797'
author:
- first_name: Stephan
full_name: Kruse, Stephan
id: '38254'
last_name: Kruse
- first_name: Pascal
full_name: Kneuper, Pascal
id: '47367'
last_name: Kneuper
- first_name: Tobias
full_name: Schwabe, Tobias
id: '39217'
last_name: Schwabe
- first_name: Heiko G.
full_name: Kurz, Heiko G.
last_name: Kurz
- first_name: Marc-Michael
full_name: Meinecke, Marc-Michael
last_name: Meinecke
- first_name: María A.
full_name: Gonzalez-Huici, María A.
last_name: Gonzalez-Huici
- first_name: J. Christoph
full_name: Scheytt, J. Christoph
id: '37144'
last_name: Scheytt
orcid: '0000-0002-5950-6618 '
citation:
ama: 'Kruse S, Kneuper P, Schwabe T, et al. Phase Noise Analysis of Photonic Radar
Systems with Optical LO Distribution. In: International Conference on Microwaves
for Intelligent Mobility (ICMIM). ; 2024.'
apa: Kruse, S., Kneuper, P., Schwabe, T., Kurz, H. G., Meinecke, M.-M., Gonzalez-Huici,
M. A., & Scheytt, J. C. (2024). Phase Noise Analysis of Photonic Radar Systems
with Optical LO Distribution. International Conference on Microwaves for Intelligent
Mobility (ICMIM).
bibtex: '@inproceedings{Kruse_Kneuper_Schwabe_Kurz_Meinecke_Gonzalez-Huici_Scheytt_2024,
place={Boppard }, title={Phase Noise Analysis of Photonic Radar Systems with Optical
LO Distribution}, booktitle={International Conference on Microwaves for Intelligent
Mobility (ICMIM)}, author={Kruse, Stephan and Kneuper, Pascal and Schwabe, Tobias
and Kurz, Heiko G. and Meinecke, Marc-Michael and Gonzalez-Huici, María A. and
Scheytt, J. Christoph}, year={2024} }'
chicago: Kruse, Stephan, Pascal Kneuper, Tobias Schwabe, Heiko G. Kurz, Marc-Michael
Meinecke, María A. Gonzalez-Huici, and J. Christoph Scheytt. “Phase Noise Analysis
of Photonic Radar Systems with Optical LO Distribution.” In International Conference
on Microwaves for Intelligent Mobility (ICMIM). Boppard , 2024.
ieee: S. Kruse et al., “Phase Noise Analysis of Photonic Radar Systems with
Optical LO Distribution,” 2024.
mla: Kruse, Stephan, et al. “Phase Noise Analysis of Photonic Radar Systems with
Optical LO Distribution.” International Conference on Microwaves for Intelligent
Mobility (ICMIM), 2024.
short: 'S. Kruse, P. Kneuper, T. Schwabe, H.G. Kurz, M.-M. Meinecke, M.A. Gonzalez-Huici,
J.C. Scheytt, in: International Conference on Microwaves for Intelligent Mobility
(ICMIM), Boppard , 2024.'
date_created: 2024-04-30T11:57:44Z
date_updated: 2025-02-25T06:05:16Z
department:
- _id: '58'
- _id: '623'
language:
- iso: eng
place: 'Boppard '
publication: International Conference on Microwaves for Intelligent Mobility (ICMIM)
related_material:
link:
- relation: research_paper
url: https://ieeexplore.ieee.org/document/10654229
status: public
title: Phase Noise Analysis of Photonic Radar Systems with Optical LO Distribution
type: conference
user_id: '38254'
year: '2024'
...
---
_id: '53800'
author:
- first_name: Stephan
full_name: Kruse, Stephan
id: '38254'
last_name: Kruse
- first_name: Jan
full_name: Brockmeier, Jan
id: '67349'
last_name: Brockmeier
- first_name: Pascal
full_name: Kneuper, Pascal
id: '47367'
last_name: Kneuper
- first_name: Tobias
full_name: Schwabe, Tobias
id: '39217'
last_name: Schwabe
- first_name: Heiko G.
full_name: Kurz, Heiko G.
last_name: Kurz
- first_name: Marc Michael
full_name: Meinecke, Marc Michael
last_name: Meinecke
- first_name: J. Christoph
full_name: Scheytt, J. Christoph
id: '37144'
last_name: Scheytt
orcid: '0000-0002-5950-6618 '
citation:
ama: 'Kruse S, Brockmeier J, Kneuper P, et al. Doppler Analysis of a Lidar-Photonic
Radar Combined Sensor System. In: International Radar Symposium (IRS).
; 2024.'
apa: Kruse, S., Brockmeier, J., Kneuper, P., Schwabe, T., Kurz, H. G., Meinecke,
M. M., & Scheytt, J. C. (2024). Doppler Analysis of a Lidar-Photonic Radar
Combined Sensor System. International Radar Symposium (IRS).
bibtex: '@inproceedings{Kruse_Brockmeier_Kneuper_Schwabe_Kurz_Meinecke_Scheytt_2024,
title={Doppler Analysis of a Lidar-Photonic Radar Combined Sensor System}, booktitle={
International Radar Symposium (IRS)}, author={Kruse, Stephan and Brockmeier, Jan
and Kneuper, Pascal and Schwabe, Tobias and Kurz, Heiko G. and Meinecke, Marc
Michael and Scheytt, J. Christoph}, year={2024} }'
chicago: Kruse, Stephan, Jan Brockmeier, Pascal Kneuper, Tobias Schwabe, Heiko G.
Kurz, Marc Michael Meinecke, and J. Christoph Scheytt. “Doppler Analysis of a
Lidar-Photonic Radar Combined Sensor System.” In International Radar Symposium
(IRS), 2024.
ieee: S. Kruse et al., “Doppler Analysis of a Lidar-Photonic Radar Combined
Sensor System,” 2024.
mla: Kruse, Stephan, et al. “Doppler Analysis of a Lidar-Photonic Radar Combined
Sensor System.” International Radar Symposium (IRS), 2024.
short: 'S. Kruse, J. Brockmeier, P. Kneuper, T. Schwabe, H.G. Kurz, M.M. Meinecke,
J.C. Scheytt, in: International Radar Symposium (IRS), 2024.'
date_created: 2024-04-30T12:03:33Z
date_updated: 2025-02-25T06:00:38Z
department:
- _id: '58'
- _id: '623'
language:
- iso: eng
publication: ' International Radar Symposium (IRS)'
related_material:
link:
- relation: research_paper
url: https://ieeexplore.ieee.org/document/10644287
status: public
title: Doppler Analysis of a Lidar-Photonic Radar Combined Sensor System
type: conference
user_id: '38254'
year: '2024'
...
---
_id: '59269'
abstract:
- lang: eng
text: Ferroelectric materials play a crucial role in a broad range of technologies
due to their unique properties that are deeply connected to the pattern and behavior
of their ferroelectric (FE) domains. Chief among them, barium titanate (BaTiO3;
BTO) sees widespread applications such as in electronics but equally is a ferroelectric
model system for fundamental research, e.g., to study the interplay of such FE
domains, the domain walls (DWs), and their macroscopic properties, owed to BTO’s
multiple and experimentally accessible phase transitions. Here, we employ Second
Harmonic Generation Microscopy (SHGM) to in situ investigate the cubic-to-tetragonal
(at ∼126°C) and the tetragonal-to-orthorhombic (at ∼5°C) phase transition in single-crystalline
BTO via three-dimensional (3D) DW mapping. We demonstrate that SHGM imaging provides
the direct visualization of FE domain switching as well as the domain dynamics
in 3D, shedding light on the interplay of the domain structure and phase transition.
These results allow us to extract the different transition temperatures locally,
to unveil the hysteresis behavior, and to determine the type of phase transition
at play (first/second order) from the recorded SHGM data. The capabilities of
SHGM in uncovering these crucial phenomena can easily be applied to other ferroelectrics
to provide new possibilities for in situ engineering of advanced ferroic devices.
article_number: '154102'
article_type: original
author:
- first_name: Benjamin
full_name: Kirbus, Benjamin
last_name: Kirbus
- first_name: Samuel D.
full_name: Seddon, Samuel D.
last_name: Seddon
- first_name: Iuliia
full_name: Kiseleva, Iuliia
last_name: Kiseleva
- first_name: Elke
full_name: Beyreuther, Elke
last_name: Beyreuther
- first_name: Michael
full_name: Rüsing, Michael
id: '22501'
last_name: Rüsing
orcid: 0000-0003-4682-4577
- first_name: Lukas M.
full_name: Eng, Lukas M.
last_name: Eng
citation:
ama: Kirbus B, Seddon SD, Kiseleva I, Beyreuther E, Rüsing M, Eng LM. Probing ferroelectric
phase transitions in barium titanate single crystals via in-situ second harmonic
generation microscopy. Journal of Applied Physics. 2024;136(15). doi:10.1063/5.0237769
apa: Kirbus, B., Seddon, S. D., Kiseleva, I., Beyreuther, E., Rüsing, M., &
Eng, L. M. (2024). Probing ferroelectric phase transitions in barium titanate
single crystals via in-situ second harmonic generation microscopy. Journal
of Applied Physics, 136(15), Article 154102. https://doi.org/10.1063/5.0237769
bibtex: '@article{Kirbus_Seddon_Kiseleva_Beyreuther_Rüsing_Eng_2024, title={Probing
ferroelectric phase transitions in barium titanate single crystals via in-situ
second harmonic generation microscopy}, volume={136}, DOI={10.1063/5.0237769},
number={15154102}, journal={Journal of Applied Physics}, publisher={AIP Publishing},
author={Kirbus, Benjamin and Seddon, Samuel D. and Kiseleva, Iuliia and Beyreuther,
Elke and Rüsing, Michael and Eng, Lukas M.}, year={2024} }'
chicago: Kirbus, Benjamin, Samuel D. Seddon, Iuliia Kiseleva, Elke Beyreuther, Michael
Rüsing, and Lukas M. Eng. “Probing Ferroelectric Phase Transitions in Barium Titanate
Single Crystals via In-Situ Second Harmonic Generation Microscopy.” Journal
of Applied Physics 136, no. 15 (2024). https://doi.org/10.1063/5.0237769.
ieee: 'B. Kirbus, S. D. Seddon, I. Kiseleva, E. Beyreuther, M. Rüsing, and L. M.
Eng, “Probing ferroelectric phase transitions in barium titanate single crystals
via in-situ second harmonic generation microscopy,” Journal of Applied Physics,
vol. 136, no. 15, Art. no. 154102, 2024, doi: 10.1063/5.0237769.'
mla: Kirbus, Benjamin, et al. “Probing Ferroelectric Phase Transitions in Barium
Titanate Single Crystals via In-Situ Second Harmonic Generation Microscopy.” Journal
of Applied Physics, vol. 136, no. 15, 154102, AIP Publishing, 2024, doi:10.1063/5.0237769.
short: B. Kirbus, S.D. Seddon, I. Kiseleva, E. Beyreuther, M. Rüsing, L.M. Eng,
Journal of Applied Physics 136 (2024).
date_created: 2025-04-02T15:57:11Z
date_updated: 2025-04-02T15:59:55Z
department:
- _id: '15'
- _id: '623'
- _id: '288'
doi: 10.1063/5.0237769
intvolume: ' 136'
issue: '15'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: ' https://doi.org/10.1063/5.0237769'
oa: '1'
publication: Journal of Applied Physics
publication_identifier:
issn:
- 0021-8979
- 1089-7550
publication_status: published
publisher: AIP Publishing
quality_controlled: '1'
status: public
title: Probing ferroelectric phase transitions in barium titanate single crystals
via in-situ second harmonic generation microscopy
type: journal_article
user_id: '22501'
volume: 136
year: '2024'
...
---
_id: '59271'
abstract:
- lang: eng
text: Lithium niobate (LNO) and lithium tantalate (LTO) see widespread use in fundamental
research and commercial technologies reaching from electronics over classical
optics to integrated quantum communication. The mixed crystal system lithium niobate
tantalate (LNT) allows for the dedicate engineering of material properties by
combining the advantages of the two parental materials LNO and LTO. Vibrational
spectroscopies such as Raman spectroscopy or (Fourier transform) infrared (IR)
spectroscopy are vital techniques to provide detailed insight into the material
properties, which is central to the analysis and optimization of devices. This
work presents a joint experimental–theoretical approach allowing to unambiguously
assign the spectral features in the LNT material family through both Raman and
IR spectroscopy, as well as providing an in‐depth explanation for the observed
scattering efficiencies based on first‐principles calculations. The phononic contribution
to the static dielectric tensor is calculated from the experimental and theoretical
data using the generalized Lyddane–Sachs–Teller relation and compared with the
results of the first‐principles calculations.
author:
- first_name: Felix
full_name: Bernhardt, Felix
last_name: Bernhardt
- first_name: Soham
full_name: Gharat, Soham
last_name: Gharat
- first_name: Alexander
full_name: Kapp, Alexander
last_name: Kapp
- first_name: Florian
full_name: Pfeiffer, Florian
last_name: Pfeiffer
- first_name: Robin
full_name: Buschbeck, Robin
last_name: Buschbeck
- first_name: Franz
full_name: Hempel, Franz
last_name: Hempel
- first_name: Oleksiy
full_name: Pashkin, Oleksiy
last_name: Pashkin
- first_name: Susanne C.
full_name: Kehr, Susanne C.
last_name: Kehr
- first_name: Michael
full_name: Rüsing, Michael
id: '22501'
last_name: Rüsing
orcid: 0000-0003-4682-4577
- first_name: Simone
full_name: Sanna, Simone
last_name: Sanna
- first_name: Lukas M.
full_name: Eng, Lukas M.
last_name: Eng
citation:
ama: 'Bernhardt F, Gharat S, Kapp A, et al. Lattice Dynamics of LiNb(1–x)Ta(x)O3
Solid Solutions: Theory and Experiment. physica status solidi (a). 2024;222(1):2300968.
doi:10.1002/pssa.202300968'
apa: 'Bernhardt, F., Gharat, S., Kapp, A., Pfeiffer, F., Buschbeck, R., Hempel,
F., Pashkin, O., Kehr, S. C., Rüsing, M., Sanna, S., & Eng, L. M. (2024).
Lattice Dynamics of LiNb(1–x)Ta(x)O3 Solid Solutions: Theory and Experiment. Physica
Status Solidi (a), 222(1), 2300968. https://doi.org/10.1002/pssa.202300968'
bibtex: '@article{Bernhardt_Gharat_Kapp_Pfeiffer_Buschbeck_Hempel_Pashkin_Kehr_Rüsing_Sanna_et
al._2024, title={Lattice Dynamics of LiNb(1–x)Ta(x)O3 Solid Solutions: Theory
and Experiment}, volume={222}, DOI={10.1002/pssa.202300968},
number={1}, journal={physica status solidi (a)}, publisher={Wiley}, author={Bernhardt,
Felix and Gharat, Soham and Kapp, Alexander and Pfeiffer, Florian and Buschbeck,
Robin and Hempel, Franz and Pashkin, Oleksiy and Kehr, Susanne C. and Rüsing,
Michael and Sanna, Simone and et al.}, year={2024}, pages={2300968} }'
chicago: 'Bernhardt, Felix, Soham Gharat, Alexander Kapp, Florian Pfeiffer, Robin
Buschbeck, Franz Hempel, Oleksiy Pashkin, et al. “Lattice Dynamics of LiNb(1–x)Ta(x)O3
Solid Solutions: Theory and Experiment.” Physica Status Solidi (a) 222,
no. 1 (2024): 2300968. https://doi.org/10.1002/pssa.202300968.'
ieee: 'F. Bernhardt et al., “Lattice Dynamics of LiNb(1–x)Ta(x)O3 Solid Solutions:
Theory and Experiment,” physica status solidi (a), vol. 222, no. 1, p.
2300968, 2024, doi: 10.1002/pssa.202300968.'
mla: 'Bernhardt, Felix, et al. “Lattice Dynamics of LiNb(1–x)Ta(x)O3 Solid Solutions:
Theory and Experiment.” Physica Status Solidi (a), vol. 222, no. 1, Wiley,
2024, p. 2300968, doi:10.1002/pssa.202300968.'
short: F. Bernhardt, S. Gharat, A. Kapp, F. Pfeiffer, R. Buschbeck, F. Hempel, O.
Pashkin, S.C. Kehr, M. Rüsing, S. Sanna, L.M. Eng, Physica Status Solidi (a) 222
(2024) 2300968.
date_created: 2025-04-02T16:04:58Z
date_updated: 2025-04-02T16:07:19Z
department:
- _id: '15'
- _id: '623'
- _id: '288'
doi: 10.1002/pssa.202300968
intvolume: ' 222'
issue: '1'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://doi.org/10.1002/pssa.202300968
oa: '1'
page: '2300968'
publication: physica status solidi (a)
publication_identifier:
issn:
- 1862-6300
- 1862-6319
publication_status: published
publisher: Wiley
status: public
title: 'Lattice Dynamics of LiNb(1–x)Ta(x)O3 Solid Solutions: Theory and Experiment'
type: journal_article
user_id: '22501'
volume: 222
year: '2024'
...
---
_id: '59270'
abstract:
- lang: eng
text: Lithium niobate tantalate (LiNb1−xTaxO3, LNT) solid solutions offer exciting
new possibilities for applications ranging from optics, piezotronics, and electronics
beyond the capabilities of the widely used singular compounds of lithium niobate
(LiNbO3, LN) or lithium tantalate (LiTaO3, LT). Crystal growth of homogeneous
LNT single crystals by the Czochralski method is still challenging. One key aspect
of homogeneous growth is the accurate knowledge of thermal conductivity through
the crystal boule during the growth, which is central to control the crystal growth.
Therefore, the temperature dependent thermal conductivity of pure LN, LT, and
LNT solid solutions, as well as of selected doped LN and LT crystals (Mg, Zn)
was investigated across the temperature range from 300 to 1300 K. The results
that span across the whole composition range can directly be applied for optimizing
growth conditions of both LNT solid solutions as well as doped and undoped LN
and LT crystals.
article_number: '176549'
article_type: original
author:
- first_name: Umar
full_name: Bashir, Umar
last_name: Bashir
- first_name: Michael
full_name: Rüsing, Michael
id: '22501'
last_name: Rüsing
orcid: 0000-0003-4682-4577
- first_name: Detlef
full_name: Klimm, Detlef
last_name: Klimm
- first_name: Roberts
full_name: Blukis, Roberts
last_name: Blukis
- first_name: Boris
full_name: Koppitz, Boris
last_name: Koppitz
- first_name: Lukas M.
full_name: Eng, Lukas M.
last_name: Eng
- first_name: Matthias
full_name: Bickermann, Matthias
last_name: Bickermann
- first_name: Steffen
full_name: Ganschow, Steffen
last_name: Ganschow
citation:
ama: Bashir U, Rüsing M, Klimm D, et al. Thermal conductivity in solid solutions
of lithium niobate tantalate single crystals from 300 K up to 1300 K. Journal
of Alloys and Compounds. 2024;1008. doi:10.1016/j.jallcom.2024.176549
apa: Bashir, U., Rüsing, M., Klimm, D., Blukis, R., Koppitz, B., Eng, L. M., Bickermann,
M., & Ganschow, S. (2024). Thermal conductivity in solid solutions of lithium
niobate tantalate single crystals from 300 K up to 1300 K. Journal of Alloys
and Compounds, 1008, Article 176549. https://doi.org/10.1016/j.jallcom.2024.176549
bibtex: '@article{Bashir_Rüsing_Klimm_Blukis_Koppitz_Eng_Bickermann_Ganschow_2024,
title={Thermal conductivity in solid solutions of lithium niobate tantalate single
crystals from 300 K up to 1300 K}, volume={1008}, DOI={10.1016/j.jallcom.2024.176549},
number={176549}, journal={Journal of Alloys and Compounds}, publisher={Elsevier
BV}, author={Bashir, Umar and Rüsing, Michael and Klimm, Detlef and Blukis, Roberts
and Koppitz, Boris and Eng, Lukas M. and Bickermann, Matthias and Ganschow, Steffen},
year={2024} }'
chicago: Bashir, Umar, Michael Rüsing, Detlef Klimm, Roberts Blukis, Boris Koppitz,
Lukas M. Eng, Matthias Bickermann, and Steffen Ganschow. “Thermal Conductivity
in Solid Solutions of Lithium Niobate Tantalate Single Crystals from 300 K up
to 1300 K.” Journal of Alloys and Compounds 1008 (2024). https://doi.org/10.1016/j.jallcom.2024.176549.
ieee: 'U. Bashir et al., “Thermal conductivity in solid solutions of lithium
niobate tantalate single crystals from 300 K up to 1300 K,” Journal of Alloys
and Compounds, vol. 1008, Art. no. 176549, 2024, doi: 10.1016/j.jallcom.2024.176549.'
mla: Bashir, Umar, et al. “Thermal Conductivity in Solid Solutions of Lithium Niobate
Tantalate Single Crystals from 300 K up to 1300 K.” Journal of Alloys and Compounds,
vol. 1008, 176549, Elsevier BV, 2024, doi:10.1016/j.jallcom.2024.176549.
short: U. Bashir, M. Rüsing, D. Klimm, R. Blukis, B. Koppitz, L.M. Eng, M. Bickermann,
S. Ganschow, Journal of Alloys and Compounds 1008 (2024).
date_created: 2025-04-02T16:00:56Z
date_updated: 2025-04-02T16:02:26Z
department:
- _id: '15'
- _id: '288'
- _id: '623'
doi: 10.1016/j.jallcom.2024.176549
intvolume: ' 1008'
language:
- iso: eng
publication: Journal of Alloys and Compounds
publication_identifier:
issn:
- 0925-8388
publication_status: published
publisher: Elsevier BV
quality_controlled: '1'
status: public
title: Thermal conductivity in solid solutions of lithium niobate tantalate single
crystals from 300 K up to 1300 K
type: journal_article
user_id: '22501'
volume: 1008
year: '2024'
...
---
_id: '59272'
abstract:
- lang: eng
text: 'Ferroelectrics such as LiNbO3 (LN) are wide-band-gap insulators that may
show a high local electric conductivity at the domain walls (DWs). The latter
are interfaces separating regions of noncollinear polarization, which can be manipulated
to build integrated nanoelectronic elements. In the present work, we model different
DW types in LN from first principles. Our models reveal the DW morphology and
shed light on their electronic properties: A strong band bending is predicted
for charged DWs, leading to local metallicity. Defect trapping at the DW may further
enhance the electric conductivity.'
article_number: L042015
author:
- first_name: Leonard M.
full_name: Verhoff, Leonard M.
last_name: Verhoff
- first_name: Mike N.
full_name: Pionteck, Mike N.
last_name: Pionteck
- first_name: Michael
full_name: Rüsing, Michael
id: '22501'
last_name: Rüsing
orcid: 0000-0003-4682-4577
- first_name: Holger
full_name: Fritze, Holger
last_name: Fritze
- first_name: Lukas M.
full_name: Eng, Lukas M.
last_name: Eng
- first_name: Simone
full_name: Sanna, Simone
last_name: Sanna
citation:
ama: 'Verhoff LM, Pionteck MN, Rüsing M, Fritze H, Eng LM, Sanna S. Two-dimensional
electronic conductivity in insulating ferroelectrics: Peculiar properties of domain
walls. Physical Review Research. 2024;6(4). doi:10.1103/physrevresearch.6.l042015'
apa: 'Verhoff, L. M., Pionteck, M. N., Rüsing, M., Fritze, H., Eng, L. M., &
Sanna, S. (2024). Two-dimensional electronic conductivity in insulating ferroelectrics:
Peculiar properties of domain walls. Physical Review Research, 6(4),
Article L042015. https://doi.org/10.1103/physrevresearch.6.l042015'
bibtex: '@article{Verhoff_Pionteck_Rüsing_Fritze_Eng_Sanna_2024, title={Two-dimensional
electronic conductivity in insulating ferroelectrics: Peculiar properties of domain
walls}, volume={6}, DOI={10.1103/physrevresearch.6.l042015},
number={4L042015}, journal={Physical Review Research}, publisher={American Physical
Society (APS)}, author={Verhoff, Leonard M. and Pionteck, Mike N. and Rüsing,
Michael and Fritze, Holger and Eng, Lukas M. and Sanna, Simone}, year={2024} }'
chicago: 'Verhoff, Leonard M., Mike N. Pionteck, Michael Rüsing, Holger Fritze,
Lukas M. Eng, and Simone Sanna. “Two-Dimensional Electronic Conductivity in Insulating
Ferroelectrics: Peculiar Properties of Domain Walls.” Physical Review Research
6, no. 4 (2024). https://doi.org/10.1103/physrevresearch.6.l042015.'
ieee: 'L. M. Verhoff, M. N. Pionteck, M. Rüsing, H. Fritze, L. M. Eng, and S. Sanna,
“Two-dimensional electronic conductivity in insulating ferroelectrics: Peculiar
properties of domain walls,” Physical Review Research, vol. 6, no. 4, Art.
no. L042015, 2024, doi: 10.1103/physrevresearch.6.l042015.'
mla: 'Verhoff, Leonard M., et al. “Two-Dimensional Electronic Conductivity in Insulating
Ferroelectrics: Peculiar Properties of Domain Walls.” Physical Review Research,
vol. 6, no. 4, L042015, American Physical Society (APS), 2024, doi:10.1103/physrevresearch.6.l042015.'
short: L.M. Verhoff, M.N. Pionteck, M. Rüsing, H. Fritze, L.M. Eng, S. Sanna, Physical
Review Research 6 (2024).
date_created: 2025-04-02T16:08:55Z
date_updated: 2025-04-02T16:10:59Z
department:
- _id: '623'
- _id: '288'
- _id: '15'
doi: 10.1103/physrevresearch.6.l042015
intvolume: ' 6'
issue: '4'
language:
- iso: eng
main_file_link:
- url: https://jlupub.ub.uni-giessen.de/server/api/core/bitstreams/fb2b09e6-c0f8-4209-99a1-79fc81d9b1f9/content
publication: Physical Review Research
publication_identifier:
issn:
- 2643-1564
publication_status: published
publisher: American Physical Society (APS)
status: public
title: 'Two-dimensional electronic conductivity in insulating ferroelectrics: Peculiar
properties of domain walls'
type: journal_article
user_id: '22501'
volume: 6
year: '2024'
...
---
_id: '59273'
abstract:
- lang: eng
text: Ferroelectric domain walls (DWs) are promising structures for assembling future
nano-electronic circuit elements on a larger scale since reporting domain wall
currents of up to 1 mA per single DW. One key requirement hereto is their reproducible
manufacturing by gaining preparative control over domain size and domain wall
conductivity (DWC). To date, most works on DWC have focused on exploring the fundamental
electrical properties of individual DWs within single-shot experiments, with an
emphasis on quantifying the origins of DWC. Very few reports exist when it comes
to comparing the DWC properties between two separate DWs, and literally nothing
exists where issues of reproducibility in DWC devices have been addressed. To
fill this gap while facing the challenge of finding guidelines for achieving predictable
DWC performance, we report on a procedure that allows us to reproducibly prepare
single hexagonal domains of a predefined diameter into uniaxial ferroelectric
lithium niobate single crystals of 200 and 300 μm thickness, respectively. We
show that the domain diameter can be controlled with an uncertainty of a few percent.
As-grown DWs are then subjected to a standard procedure of current-limited high-voltage
DWC enhancement, and they repetitively reach a DWC increase of six orders of magnitude.
While all resulting DWs show significantly enhanced DWC values, their individual
current–voltage (I–V) characteristics exhibit different shapes, which can be explained
by variations in their 3D real structure reflecting local heterogeneities by defects,
DW pinning, and surface-near DW inclination.
article_type: original
author:
- first_name: Julius
full_name: Ratzenberger, Julius
last_name: Ratzenberger
- first_name: Iuliia
full_name: Kiseleva, Iuliia
last_name: Kiseleva
- first_name: Boris
full_name: Koppitz, Boris
last_name: Koppitz
- first_name: Elke
full_name: Beyreuther, Elke
last_name: Beyreuther
- first_name: Manuel
full_name: Zahn, Manuel
last_name: Zahn
- first_name: Joshua
full_name: Gössel, Joshua
last_name: Gössel
- first_name: Peter A.
full_name: Hegarty, Peter A.
last_name: Hegarty
- first_name: Zeeshan H.
full_name: Amber, Zeeshan H.
last_name: Amber
- first_name: Michael
full_name: Rüsing, Michael
id: '22501'
last_name: Rüsing
orcid: 0000-0003-4682-4577
- first_name: Lukas M.
full_name: Eng, Lukas M.
last_name: Eng
citation:
ama: Ratzenberger J, Kiseleva I, Koppitz B, et al. Toward the reproducible fabrication
of conductive ferroelectric domain walls into lithium niobate bulk single crystals.
Journal of Applied Physics. 2024;136(10):104302. doi:10.1063/5.0219300
apa: Ratzenberger, J., Kiseleva, I., Koppitz, B., Beyreuther, E., Zahn, M., Gössel,
J., Hegarty, P. A., Amber, Z. H., Rüsing, M., & Eng, L. M. (2024). Toward
the reproducible fabrication of conductive ferroelectric domain walls into lithium
niobate bulk single crystals. Journal of Applied Physics, 136(10),
104302. https://doi.org/10.1063/5.0219300
bibtex: '@article{Ratzenberger_Kiseleva_Koppitz_Beyreuther_Zahn_Gössel_Hegarty_Amber_Rüsing_Eng_2024,
title={Toward the reproducible fabrication of conductive ferroelectric domain
walls into lithium niobate bulk single crystals}, volume={136}, DOI={10.1063/5.0219300},
number={10}, journal={Journal of Applied Physics}, publisher={AIP Publishing},
author={Ratzenberger, Julius and Kiseleva, Iuliia and Koppitz, Boris and Beyreuther,
Elke and Zahn, Manuel and Gössel, Joshua and Hegarty, Peter A. and Amber, Zeeshan
H. and Rüsing, Michael and Eng, Lukas M.}, year={2024}, pages={104302} }'
chicago: 'Ratzenberger, Julius, Iuliia Kiseleva, Boris Koppitz, Elke Beyreuther,
Manuel Zahn, Joshua Gössel, Peter A. Hegarty, Zeeshan H. Amber, Michael Rüsing,
and Lukas M. Eng. “Toward the Reproducible Fabrication of Conductive Ferroelectric
Domain Walls into Lithium Niobate Bulk Single Crystals.” Journal of Applied
Physics 136, no. 10 (2024): 104302. https://doi.org/10.1063/5.0219300.'
ieee: 'J. Ratzenberger et al., “Toward the reproducible fabrication of conductive
ferroelectric domain walls into lithium niobate bulk single crystals,” Journal
of Applied Physics, vol. 136, no. 10, p. 104302, 2024, doi: 10.1063/5.0219300.'
mla: Ratzenberger, Julius, et al. “Toward the Reproducible Fabrication of Conductive
Ferroelectric Domain Walls into Lithium Niobate Bulk Single Crystals.” Journal
of Applied Physics, vol. 136, no. 10, AIP Publishing, 2024, p. 104302, doi:10.1063/5.0219300.
short: J. Ratzenberger, I. Kiseleva, B. Koppitz, E. Beyreuther, M. Zahn, J. Gössel,
P.A. Hegarty, Z.H. Amber, M. Rüsing, L.M. Eng, Journal of Applied Physics 136
(2024) 104302.
date_created: 2025-04-02T16:12:29Z
date_updated: 2025-04-02T16:14:31Z
department:
- _id: '288'
- _id: '15'
- _id: '623'
doi: 10.1063/5.0219300
intvolume: ' 136'
issue: '10'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: ' https://doi.org/10.1063/5.0219300'
oa: '1'
page: '104302'
publication: Journal of Applied Physics
publication_identifier:
issn:
- 0021-8979
- 1089-7550
publication_status: published
publisher: AIP Publishing
quality_controlled: '1'
status: public
title: Toward the reproducible fabrication of conductive ferroelectric domain walls
into lithium niobate bulk single crystals
type: journal_article
user_id: '22501'
volume: 136
year: '2024'
...
---
_id: '59274'
abstract:
- lang: eng
text: 'Recently, ion exchange (IE) has been used to periodically modify the coercive
field (Ec) of the crystal prior to periodic poling, to fabricate fine-pitch domain
structures in Rb-doped KTiOPO4 (RKTP). Here, we use micro-Raman spectroscopy to
understand the impact of IE on the vibrational modes related to the Rb/K lattice
sites, TiO octahedra, and PO4 tetrahedra, which all form the basis of the RKTP
crystal structure. We analyze the Raman spectra of three different RKTP samples:
(1) a RKTP sample that shows a poled domain grating only, (2) a RKTP sample that
has an Ec grating only, and (3) a RKTP sample that has both an Ec and a domain
grating of the nominally same spacing. This allows us to determine the impact
of IE on the vibrational modes of RKTP. We characterize the changes in the lower
Raman peaks related to the alkali-metal ions, as well as observe lattice modifications
induced by the incorporation of Rb+ that extend further into the crystal bulk
than the expected IE depth. Moreover, the influence of IE on the domain walls
is also manifested in their Raman peak shift. We discuss our results in terms
of the deformation of the PO4and TiO groups. Our results highlight the intricate
impact of IE on the crystal structure and how it facilitates periodic poling,
paving the way for further development of the Ec-engineering technique.'
article_number: '214115'
article_type: original
author:
- first_name: Cherrie S. J.
full_name: Lee, Cherrie S. J.
last_name: Lee
- first_name: Carlota
full_name: Canalias, Carlota
last_name: Canalias
- first_name: Robin
full_name: Buschbeck, Robin
last_name: Buschbeck
- first_name: Boris
full_name: Koppitz, Boris
last_name: Koppitz
- first_name: Franz
full_name: Hempel, Franz
last_name: Hempel
- first_name: Zeeshan
full_name: Amber, Zeeshan
last_name: Amber
- first_name: Lukas M.
full_name: Eng, Lukas M.
last_name: Eng
- first_name: Michael
full_name: Rüsing, Michael
id: '22501'
last_name: Rüsing
orcid: 0000-0003-4682-4577
citation:
ama: 'Lee CSJ, Canalias C, Buschbeck R, et al. Impact of ion exchange on vibrational
modes in Rb-doped KTiOPO4: A Raman spectroscopy study on the interplay between
ion exchange and polarization switching. Physical Review B. 2024;110(21).
doi:10.1103/physrevb.110.214115'
apa: 'Lee, C. S. J., Canalias, C., Buschbeck, R., Koppitz, B., Hempel, F., Amber,
Z., Eng, L. M., & Rüsing, M. (2024). Impact of ion exchange on vibrational
modes in Rb-doped KTiOPO4: A Raman spectroscopy study on the interplay between
ion exchange and polarization switching. Physical Review B, 110(21),
Article 214115. https://doi.org/10.1103/physrevb.110.214115'
bibtex: '@article{Lee_Canalias_Buschbeck_Koppitz_Hempel_Amber_Eng_Rüsing_2024, title={Impact
of ion exchange on vibrational modes in Rb-doped KTiOPO4: A Raman spectroscopy
study on the interplay between ion exchange and polarization switching}, volume={110},
DOI={10.1103/physrevb.110.214115},
number={21214115}, journal={Physical Review B}, publisher={American Physical Society
(APS)}, author={Lee, Cherrie S. J. and Canalias, Carlota and Buschbeck, Robin
and Koppitz, Boris and Hempel, Franz and Amber, Zeeshan and Eng, Lukas M. and
Rüsing, Michael}, year={2024} }'
chicago: 'Lee, Cherrie S. J., Carlota Canalias, Robin Buschbeck, Boris Koppitz,
Franz Hempel, Zeeshan Amber, Lukas M. Eng, and Michael Rüsing. “Impact of Ion
Exchange on Vibrational Modes in Rb-Doped KTiOPO4: A Raman Spectroscopy Study
on the Interplay between Ion Exchange and Polarization Switching.” Physical
Review B 110, no. 21 (2024). https://doi.org/10.1103/physrevb.110.214115.'
ieee: 'C. S. J. Lee et al., “Impact of ion exchange on vibrational modes
in Rb-doped KTiOPO4: A Raman spectroscopy study on the interplay between ion exchange
and polarization switching,” Physical Review B, vol. 110, no. 21, Art.
no. 214115, 2024, doi: 10.1103/physrevb.110.214115.'
mla: 'Lee, Cherrie S. J., et al. “Impact of Ion Exchange on Vibrational Modes in
Rb-Doped KTiOPO4: A Raman Spectroscopy Study on the Interplay between Ion Exchange
and Polarization Switching.” Physical Review B, vol. 110, no. 21, 214115,
American Physical Society (APS), 2024, doi:10.1103/physrevb.110.214115.'
short: C.S.J. Lee, C. Canalias, R. Buschbeck, B. Koppitz, F. Hempel, Z. Amber, L.M.
Eng, M. Rüsing, Physical Review B 110 (2024).
date_created: 2025-04-02T16:14:44Z
date_updated: 2025-04-02T16:18:34Z
department:
- _id: '288'
- _id: '15'
- _id: '623'
doi: 10.1103/physrevb.110.214115
intvolume: ' 110'
issue: '21'
language:
- iso: eng
publication: Physical Review B
publication_identifier:
issn:
- 2469-9950
- 2469-9969
publication_status: published
publisher: American Physical Society (APS)
status: public
title: 'Impact of ion exchange on vibrational modes in Rb-doped KTiOPO4: A Raman spectroscopy
study on the interplay between ion exchange and polarization switching'
type: journal_article
user_id: '22501'
volume: 110
year: '2024'
...
---
_id: '59275'
abstract:
- lang: eng
text: Studying and understanding many‐body interactions, particularly electron‐boson
interactions, is essential for a deeper elucidation of fundamental physical phenomena
and the development of novel material functionalities. Here, this aspect is explored
in the weak itinerant ferromagnet LaCo2P2 by means of momentum‐resolved photoelectron
spectroscopy (ARPES) and first‐principles calculations. The detailed ARPES patterns
enable to unveil bulk and surface bands, spin splittings due to Rashba and exchange
interactions, as well as the evolution of bands with temperature, which altogether
creates a solid foundation for theoretical studies. The latter has allowed to
establish the impact of electron‐boson interactions on the electronic structure,
that are reflected in its strong renormalization driven by electron‐magnon interaction
and the emergence of distinctive kinks of surface and bulk electron bands due
to significant electron‐phonon coupling. Our results highlight the distinct impact
of electron‐boson interactions on the electronic structure, particularly on the
itinerant d states. Similar electronic states are observed in the isostructural
iron pnictides, where electron‐boson interactions play a crucial role in the emergence
of superconductivity. It is believed that further studies of material systems
involving both magnetically active d‐ and f‐sublattices will reveal more advanced
phenomena in the bulk and at distinct surfaces, driven by a combination of factors
including Rashba and Kondo effects, exchange magnetism, and electron‐boson interactions.
author:
- first_name: D. Yu.
full_name: Usachov, D. Yu.
last_name: Usachov
- first_name: K.
full_name: Ali, K.
last_name: Ali
- first_name: G.
full_name: Poelchen, G.
last_name: Poelchen
- first_name: M.
full_name: Mende, M.
last_name: Mende
- first_name: S.
full_name: Schulz, S.
last_name: Schulz
- first_name: M.
full_name: Peters, M.
last_name: Peters
- first_name: K.
full_name: Bokai, K.
last_name: Bokai
- first_name: I. Yu.
full_name: Sklyadneva, I. Yu.
last_name: Sklyadneva
- first_name: V.
full_name: Stolyarov, V.
last_name: Stolyarov
- first_name: E. V.
full_name: Chulkov, E. V.
last_name: Chulkov
- first_name: K.
full_name: Kliemt, K.
last_name: Kliemt
- first_name: S.
full_name: Paischer, S.
last_name: Paischer
- first_name: P. A.
full_name: Buczek, P. A.
last_name: Buczek
- first_name: R.
full_name: Heid, R.
last_name: Heid
- first_name: F.
full_name: Hempel, F.
last_name: Hempel
- first_name: Michael
full_name: Rüsing, Michael
id: '22501'
last_name: Rüsing
orcid: 0000-0003-4682-4577
- first_name: A.
full_name: Ernst, A.
last_name: Ernst
- first_name: C.
full_name: Krellner, C.
last_name: Krellner
- first_name: S. V.
full_name: Eremeev, S. V.
last_name: Eremeev
- first_name: D. V.
full_name: Vyalikh, D. V.
last_name: Vyalikh
citation:
ama: Usachov DYu, Ali K, Poelchen G, et al. Unveiling Electron‐Phonon and Electron‐Magnon
Interactions in the Weak Itinerant Ferromagnet LaCo2P2. Advanced Physics Research.
Published online 2024. doi:10.1002/apxr.202400137
apa: Usachov, D. Yu., Ali, K., Poelchen, G., Mende, M., Schulz, S., Peters, M.,
Bokai, K., Sklyadneva, I. Yu., Stolyarov, V., Chulkov, E. V., Kliemt, K., Paischer,
S., Buczek, P. A., Heid, R., Hempel, F., Rüsing, M., Ernst, A., Krellner, C.,
Eremeev, S. V., & Vyalikh, D. V. (2024). Unveiling Electron‐Phonon and Electron‐Magnon
Interactions in the Weak Itinerant Ferromagnet LaCo2P2. Advanced Physics Research.
https://doi.org/10.1002/apxr.202400137
bibtex: '@article{Usachov_Ali_Poelchen_Mende_Schulz_Peters_Bokai_Sklyadneva_Stolyarov_Chulkov_et
al._2024, title={Unveiling Electron‐Phonon and Electron‐Magnon Interactions in
the Weak Itinerant Ferromagnet LaCo2P2}, DOI={10.1002/apxr.202400137},
journal={Advanced Physics Research}, publisher={Wiley}, author={Usachov, D. Yu.
and Ali, K. and Poelchen, G. and Mende, M. and Schulz, S. and Peters, M. and Bokai,
K. and Sklyadneva, I. Yu. and Stolyarov, V. and Chulkov, E. V. and et al.}, year={2024}
}'
chicago: Usachov, D. Yu., K. Ali, G. Poelchen, M. Mende, S. Schulz, M. Peters, K.
Bokai, et al. “Unveiling Electron‐Phonon and Electron‐Magnon Interactions in the
Weak Itinerant Ferromagnet LaCo2P2.” Advanced Physics Research, 2024. https://doi.org/10.1002/apxr.202400137.
ieee: 'D. Yu. Usachov et al., “Unveiling Electron‐Phonon and Electron‐Magnon
Interactions in the Weak Itinerant Ferromagnet LaCo2P2,” Advanced Physics Research,
2024, doi: 10.1002/apxr.202400137.'
mla: Usachov, D. Yu., et al. “Unveiling Electron‐Phonon and Electron‐Magnon Interactions
in the Weak Itinerant Ferromagnet LaCo2P2.” Advanced Physics Research,
Wiley, 2024, doi:10.1002/apxr.202400137.
short: D.Yu. Usachov, K. Ali, G. Poelchen, M. Mende, S. Schulz, M. Peters, K. Bokai,
I.Yu. Sklyadneva, V. Stolyarov, E.V. Chulkov, K. Kliemt, S. Paischer, P.A. Buczek,
R. Heid, F. Hempel, M. Rüsing, A. Ernst, C. Krellner, S.V. Eremeev, D.V. Vyalikh,
Advanced Physics Research (2024).
date_created: 2025-04-02T16:18:56Z
date_updated: 2025-04-02T16:20:41Z
department:
- _id: '288'
- _id: '623'
- _id: '15'
doi: 10.1002/apxr.202400137
language:
- iso: eng
publication: Advanced Physics Research
publication_identifier:
issn:
- 2751-1200
- 2751-1200
publication_status: published
publisher: Wiley
quality_controlled: '1'
status: public
title: Unveiling Electron‐Phonon and Electron‐Magnon Interactions in the Weak Itinerant
Ferromagnet LaCo2P2
type: journal_article
user_id: '22501'
year: '2024'
...
---
_id: '54967'
abstract:
- lang: eng
text: 'Ferroelectric domain wall conductivity (DWC) is an intriguing and
promising functional property that can be elegantly controlled and steered through
a variety of external stimuli such as electric and mechanical fields. Optical-field
control, as a noninvasive and flexible tool, has rarely been applied so far, but
it significantly expands the possibility for both tuning and probing DWC. On the
one hand, as known from second-harmonic or Raman micro-spectroscopy, the optical
approach provides information on DW distribution and inclination, while simultaneously
probing the DW vibrational modes; on the other hand, photons might be applied
to directly generate charge carriers, thereby acting as a functional and spectrally
tunable probe to deduce the local absorption properties and bandgaps of conductive
DWs. Here, we report on investigating the photo-induced DWC (PI-DWC) of three
lithium niobate crystals, containing a very different number of DWs, namely: (A)
none, (B) one, and (C) many conductive DWs. All three samples are inspected for
their current–voltage behavior in darkness and for different illumination wavelengths
swept from 500 nm down to 310 nm. All samples show their maximum PI-DWC at 310 nm;
moreover, sample (C) reaches PI-DWCs of several microampere. Interestingly, a
noticeable PI-DWC is also observed for sub-bandgap illumination, hinting toward
the existence and decisive role of electronic in-gap states that contribute to
the electronic charge transport along DWs. Finally, complementary conductive atomic
force microscopy investigations under illumination proved that the PI-DWC indeed
is confined to the DW area and does not originate from photo-induced bulk conductivity.'
article_type: original
author:
- first_name: L. L.
full_name: Ding, L. L.
last_name: Ding
- first_name: E.
full_name: Beyreuther, E.
last_name: Beyreuther
- first_name: B.
full_name: Koppitz, B.
last_name: Koppitz
- first_name: K.
full_name: Kempf, K.
last_name: Kempf
- first_name: J. H.
full_name: Ren, J. H.
last_name: Ren
- first_name: W. J.
full_name: Chen, W. J.
last_name: Chen
- first_name: Michael
full_name: Rüsing, Michael
id: '22501'
last_name: Rüsing
orcid: 0000-0003-4682-4577
- first_name: Y.
full_name: Zheng, Y.
last_name: Zheng
- first_name: L. M.
full_name: Eng, L. M.
last_name: Eng
citation:
ama: Ding LL, Beyreuther E, Koppitz B, et al. Comparative study of photo-induced
electronic transport along ferroelectric domain walls in lithium niobate single
crystals. Applied Physics Letters. 2024;124(25). doi:10.1063/5.0205877
apa: Ding, L. L., Beyreuther, E., Koppitz, B., Kempf, K., Ren, J. H., Chen, W. J.,
Rüsing, M., Zheng, Y., & Eng, L. M. (2024). Comparative study of photo-induced
electronic transport along ferroelectric domain walls in lithium niobate single
crystals. Applied Physics Letters, 124(25). https://doi.org/10.1063/5.0205877
bibtex: '@article{Ding_Beyreuther_Koppitz_Kempf_Ren_Chen_Rüsing_Zheng_Eng_2024,
title={Comparative study of photo-induced electronic transport along ferroelectric
domain walls in lithium niobate single crystals}, volume={124}, DOI={10.1063/5.0205877},
number={25}, journal={Applied Physics Letters}, publisher={AIP Publishing}, author={Ding,
L. L. and Beyreuther, E. and Koppitz, B. and Kempf, K. and Ren, J. H. and Chen,
W. J. and Rüsing, Michael and Zheng, Y. and Eng, L. M.}, year={2024} }'
chicago: Ding, L. L., E. Beyreuther, B. Koppitz, K. Kempf, J. H. Ren, W. J. Chen,
Michael Rüsing, Y. Zheng, and L. M. Eng. “Comparative Study of Photo-Induced Electronic
Transport along Ferroelectric Domain Walls in Lithium Niobate Single Crystals.”
Applied Physics Letters 124, no. 25 (2024). https://doi.org/10.1063/5.0205877.
ieee: 'L. L. Ding et al., “Comparative study of photo-induced electronic
transport along ferroelectric domain walls in lithium niobate single crystals,”
Applied Physics Letters, vol. 124, no. 25, 2024, doi: 10.1063/5.0205877.'
mla: Ding, L. L., et al. “Comparative Study of Photo-Induced Electronic Transport
along Ferroelectric Domain Walls in Lithium Niobate Single Crystals.” Applied
Physics Letters, vol. 124, no. 25, AIP Publishing, 2024, doi:10.1063/5.0205877.
short: L.L. Ding, E. Beyreuther, B. Koppitz, K. Kempf, J.H. Ren, W.J. Chen, M. Rüsing,
Y. Zheng, L.M. Eng, Applied Physics Letters 124 (2024).
date_created: 2024-07-01T21:03:23Z
date_updated: 2025-04-03T12:35:17Z
department:
- _id: '15'
- _id: '169'
- _id: '623'
doi: 10.1063/5.0205877
intvolume: ' 124'
issue: '25'
language:
- iso: eng
main_file_link:
- url: https://doi.org/10.1063/5.0205877
publication: Applied Physics Letters
publication_identifier:
issn:
- 0003-6951
- 1077-3118
publication_status: published
publisher: AIP Publishing
quality_controlled: '1'
status: public
title: Comparative study of photo-induced electronic transport along ferroelectric
domain walls in lithium niobate single crystals
type: journal_article
user_id: '22501'
volume: 124
year: '2024'
...
---
_id: '54966'
abstract:
- lang: eng
text: Piezoresponse force microscopy (PFM) is one of the most widespread methods
for investigating and visualizing ferroelectric domain structures down to the
nanometer length scale. PFM makes use of the direct coupling of the piezoelectric
response to the crystal lattice, and hence, it is most often applied to spatially
map the three-dimensional (3D) near-surface domain distribution of any polar or
ferroic sample. Nonetheless, since most samples investigated by PFM are at least
semiconducting or fully insulating, the electric ac field emerging from the conductive
scanning force microscopy (SFM) tip penetrates the sample and, hence, may also
couple to polar features that are deeply buried into the bulk of the sample under
investigation. Thus, in the work presented here, we experimentally and theoretically
explore the contrast and depth resolution capabilities of PFM, by analyzing the
dependence of several key parameters. These key parameters include the depth of
the buried feature, i.e., here a domain wall (DW), as well as PFM-relevant technical
parameters such as the tip radius, the PFM drive voltage and frequency, and the
signal-to-noise ratio. The theoretical predictions are experimentally verified
using x-cut periodically poled lithium niobate single crystals that are specially
prepared into wedge-shaped samples, in order to allow the buried feature, here
the DW, to be “positioned” at any depth into the bulk. This inspection essentially
contributes to the fundamental understanding in PFM contrast analysis and to the
reconstruction of 3D domain structures down to a 1 μm-penetration depth into the
sample.
article_type: original
author:
- first_name: Matthias
full_name: Roeper, Matthias
last_name: Roeper
- first_name: Samuel D.
full_name: Seddon, Samuel D.
last_name: Seddon
- first_name: Zeeshan H.
full_name: Amber, Zeeshan H.
last_name: Amber
- first_name: Michael
full_name: Rüsing, Michael
id: '22501'
last_name: Rüsing
orcid: 0000-0003-4682-4577
- first_name: Lukas M.
full_name: Eng, Lukas M.
last_name: Eng
citation:
ama: Roeper M, Seddon SD, Amber ZH, Rüsing M, Eng LM. Depth resolution in piezoresponse
force microscopy. Journal of Applied Physics. 2024;135(22). doi:10.1063/5.0206784
apa: Roeper, M., Seddon, S. D., Amber, Z. H., Rüsing, M., & Eng, L. M. (2024).
Depth resolution in piezoresponse force microscopy. Journal of Applied Physics,
135(22). https://doi.org/10.1063/5.0206784
bibtex: '@article{Roeper_Seddon_Amber_Rüsing_Eng_2024, title={Depth resolution in
piezoresponse force microscopy}, volume={135}, DOI={10.1063/5.0206784},
number={22}, journal={Journal of Applied Physics}, publisher={AIP Publishing},
author={Roeper, Matthias and Seddon, Samuel D. and Amber, Zeeshan H. and Rüsing,
Michael and Eng, Lukas M.}, year={2024} }'
chicago: Roeper, Matthias, Samuel D. Seddon, Zeeshan H. Amber, Michael Rüsing, and
Lukas M. Eng. “Depth Resolution in Piezoresponse Force Microscopy.” Journal
of Applied Physics 135, no. 22 (2024). https://doi.org/10.1063/5.0206784.
ieee: 'M. Roeper, S. D. Seddon, Z. H. Amber, M. Rüsing, and L. M. Eng, “Depth resolution
in piezoresponse force microscopy,” Journal of Applied Physics, vol. 135,
no. 22, 2024, doi: 10.1063/5.0206784.'
mla: Roeper, Matthias, et al. “Depth Resolution in Piezoresponse Force Microscopy.”
Journal of Applied Physics, vol. 135, no. 22, AIP Publishing, 2024, doi:10.1063/5.0206784.
short: M. Roeper, S.D. Seddon, Z.H. Amber, M. Rüsing, L.M. Eng, Journal of Applied
Physics 135 (2024).
date_created: 2024-07-01T21:00:43Z
date_updated: 2025-04-03T12:35:34Z
department:
- _id: '15'
- _id: '169'
- _id: '288'
- _id: '623'
doi: 10.1063/5.0206784
intvolume: ' 135'
issue: '22'
keyword:
- Ferroelectrics
- lithium niobate
- piezoresponse force microscopy
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://doi.org/10.1063/5.0206784
oa: '1'
publication: Journal of Applied Physics
publication_identifier:
issn:
- 0021-8979
- 1089-7550
publication_status: published
publisher: AIP Publishing
quality_controlled: '1'
status: public
title: Depth resolution in piezoresponse force microscopy
type: journal_article
user_id: '22501'
volume: 135
year: '2024'
...
---
_id: '59259'
author:
- first_name: Tobias
full_name: Schwabe, Tobias
id: '39217'
last_name: Schwabe
- first_name: Michael
full_name: Rüsing, Michael
id: '22501'
last_name: Rüsing
orcid: 0000-0003-4682-4577
- first_name: Niels
full_name: Staal, Niels
last_name: Staal
- first_name: Max
full_name: Schwengelbeck, Max
last_name: Schwengelbeck
- first_name: Laura
full_name: Bollmers, Laura
id: '61375'
last_name: Bollmers
- first_name: Laura
full_name: Padberg, Laura
id: '40300'
last_name: Padberg
- first_name: Christof
full_name: Eigner, Christof
id: '13244'
last_name: Eigner
orcid: https://orcid.org/0000-0002-5693-3083
- first_name: Christine
full_name: Silberhorn, Christine
id: '26263'
last_name: Silberhorn
- first_name: J. Christoph
full_name: Scheytt, J. Christoph
id: '37144'
last_name: Scheytt
orcid: '0000-0002-5950-6618 '
citation:
ama: Schwabe T, Rüsing M, Staal N, et al. Quantum Photonic Systems in CMOS Compatible
Silicon Nitride Technology . Zenodo; 2024. doi:10.5281/zenodo.15124929
apa: Schwabe, T., Rüsing, M., Staal, N., Schwengelbeck, M., Bollmers, L., Padberg,
L., Eigner, C., Silberhorn, C., & Scheytt, J. C. (2024). Quantum photonic
systems in CMOS compatible silicon nitride technology . Zenodo. https://doi.org/10.5281/zenodo.15124929
bibtex: '@book{Schwabe_Rüsing_Staal_Schwengelbeck_Bollmers_Padberg_Eigner_Silberhorn_Scheytt_2024,
title={Quantum photonic systems in CMOS compatible silicon nitride technology
}, DOI={10.5281/zenodo.15124929},
publisher={Zenodo}, author={Schwabe, Tobias and Rüsing, Michael and Staal, Niels
and Schwengelbeck, Max and Bollmers, Laura and Padberg, Laura and Eigner, Christof
and Silberhorn, Christine and Scheytt, J. Christoph}, year={2024} }'
chicago: Schwabe, Tobias, Michael Rüsing, Niels Staal, Max Schwengelbeck, Laura
Bollmers, Laura Padberg, Christof Eigner, Christine Silberhorn, and J. Christoph
Scheytt. Quantum Photonic Systems in CMOS Compatible Silicon Nitride Technology
. Zenodo, 2024. https://doi.org/10.5281/zenodo.15124929.
ieee: T. Schwabe et al., Quantum photonic systems in CMOS compatible silicon
nitride technology . Zenodo, 2024.
mla: Schwabe, Tobias, et al. Quantum Photonic Systems in CMOS Compatible Silicon
Nitride Technology . Zenodo, 2024, doi:10.5281/zenodo.15124929.
short: T. Schwabe, M. Rüsing, N. Staal, M. Schwengelbeck, L. Bollmers, L. Padberg,
C. Eigner, C. Silberhorn, J.C. Scheytt, Quantum Photonic Systems in CMOS Compatible
Silicon Nitride Technology , Zenodo, 2024.
date_created: 2025-04-02T11:24:23Z
date_updated: 2025-04-03T12:34:56Z
department:
- _id: '288'
- _id: '15'
- _id: '623'
doi: 10.5281/zenodo.15124929
language:
- iso: eng
publisher: Zenodo
status: public
title: 'Quantum photonic systems in CMOS compatible silicon nitride technology '
type: misc
user_id: '22501'
year: '2024'
...
---
_id: '50273'
abstract:
- lang: eng
text: "The Polynomial-Time Hierarchy ($\\mathsf{PH}$) is a staple of classical\r\ncomplexity
theory, with applications spanning randomized computation to circuit\r\nlower
bounds to ''quantum advantage'' analyses for near-term quantum computers.\r\nQuantumly,
however, despite the fact that at least \\emph{four} definitions of\r\nquantum
$\\mathsf{PH}$ exist, it has been challenging to prove analogues for\r\nthese
of even basic facts from $\\mathsf{PH}$. This work studies three\r\nquantum-verifier
based generalizations of $\\mathsf{PH}$, two of which are from\r\n[Gharibian,
Santha, Sikora, Sundaram, Yirka, 2022] and use classical strings\r\n($\\mathsf{QCPH}$)
and quantum mixed states ($\\mathsf{QPH}$) as proofs, and one\r\nof which is new
to this work, utilizing quantum pure states\r\n($\\mathsf{pureQPH}$) as proofs.
We first resolve several open problems from\r\n[GSSSY22], including a collapse
theorem and a Karp-Lipton theorem for\r\n$\\mathsf{QCPH}$. Then, for our new class
$\\mathsf{pureQPH}$, we show one-sided\r\nerror reduction for $\\mathsf{pureQPH}$,
as well as the first bounds relating\r\nthese quantum variants of $\\mathsf{PH}$,
namely $\\mathsf{QCPH}\\subseteq\r\n\\mathsf{pureQPH} \\subseteq \\mathsf{EXP}^{\\mathsf{PP}}$."
author:
- first_name: Avantika
full_name: Agarwal, Avantika
last_name: Agarwal
- first_name: Sevag
full_name: Gharibian, Sevag
id: '71541'
last_name: Gharibian
orcid: 0000-0002-9992-3379
- first_name: Venkata
full_name: Koppula, Venkata
last_name: Koppula
- first_name: Dorian
full_name: Rudolph, Dorian
id: '57863'
last_name: Rudolph
citation:
ama: 'Agarwal A, Gharibian S, Koppula V, Rudolph D. Quantum Polynomial Hierarchies:
Karp-Lipton, error reduction, and lower bounds. In: Proceedings of 49th International
Symposium on Mathematical Foundations of Computer Science (MFCS). Vol 306.
; 2024:7-17. doi:10.4230/LIPIcs.MFCS.2024.7'
apa: 'Agarwal, A., Gharibian, S., Koppula, V., & Rudolph, D. (2024). Quantum
Polynomial Hierarchies: Karp-Lipton, error reduction, and lower bounds. Proceedings
of 49th International Symposium on Mathematical Foundations of Computer Science
(MFCS), 306(7), 7–17. https://doi.org/10.4230/LIPIcs.MFCS.2024.7'
bibtex: '@inproceedings{Agarwal_Gharibian_Koppula_Rudolph_2024, title={Quantum Polynomial
Hierarchies: Karp-Lipton, error reduction, and lower bounds}, volume={306}, DOI={10.4230/LIPIcs.MFCS.2024.7},
number={7}, booktitle={Proceedings of 49th International Symposium on Mathematical
Foundations of Computer Science (MFCS)}, author={Agarwal, Avantika and Gharibian,
Sevag and Koppula, Venkata and Rudolph, Dorian}, year={2024}, pages={7–17} }'
chicago: 'Agarwal, Avantika, Sevag Gharibian, Venkata Koppula, and Dorian Rudolph.
“Quantum Polynomial Hierarchies: Karp-Lipton, Error Reduction, and Lower Bounds.”
In Proceedings of 49th International Symposium on Mathematical Foundations
of Computer Science (MFCS), 306:7–17, 2024. https://doi.org/10.4230/LIPIcs.MFCS.2024.7.'
ieee: 'A. Agarwal, S. Gharibian, V. Koppula, and D. Rudolph, “Quantum Polynomial
Hierarchies: Karp-Lipton, error reduction, and lower bounds,” in Proceedings
of 49th International Symposium on Mathematical Foundations of Computer Science
(MFCS), 2024, vol. 306, no. 7, pp. 7–17, doi: 10.4230/LIPIcs.MFCS.2024.7.'
mla: 'Agarwal, Avantika, et al. “Quantum Polynomial Hierarchies: Karp-Lipton, Error
Reduction, and Lower Bounds.” Proceedings of 49th International Symposium
on Mathematical Foundations of Computer Science (MFCS), vol. 306, no. 7, 2024,
pp. 7–17, doi:10.4230/LIPIcs.MFCS.2024.7.'
short: 'A. Agarwal, S. Gharibian, V. Koppula, D. Rudolph, in: Proceedings of 49th
International Symposium on Mathematical Foundations of Computer Science (MFCS),
2024, pp. 7–17.'
date_created: 2024-01-07T20:09:32Z
date_updated: 2026-05-15T08:39:23Z
department:
- _id: '7'
- _id: '623'
doi: 10.4230/LIPIcs.MFCS.2024.7
external_id:
arxiv:
- '2401.01633'
intvolume: ' 306'
issue: '7'
language:
- iso: eng
page: 7-17
publication: Proceedings of 49th International Symposium on Mathematical Foundations
of Computer Science (MFCS)
publication_status: published
status: public
title: 'Quantum Polynomial Hierarchies: Karp-Lipton, error reduction, and lower bounds'
type: conference
user_id: '71541'
volume: 306
year: '2024'
...
---
_id: '50406'
abstract:
- lang: eng
text: "What is the power of polynomial-time quantum computation with access to an
NP\r\noracle? In this work, we focus on two fundamental tasks from the study of\r\nBoolean
satisfiability (SAT) problems: search-to-decision reductions, and\r\napproximate
counting. We first show that, in strong contrast to the classical\r\nsetting where
a poly-time Turing machine requires $\\Theta(n)$ queries to an NP\r\noracle to
compute a witness to a given SAT formula, quantumly $\\Theta(\\log n)$\r\nqueries
suffice. We then show this is tight in the black-box model - any\r\nquantum algorithm
with \"NP-like\" query access to a formula requires\r\n$\\Omega(\\log n)$ queries
to extract a solution with constant probability.\r\nMoving to approximate counting
of SAT solutions, by exploiting a quantum link\r\nbetween search-to-decision reductions
and approximate counting, we show that\r\nexisting classical approximate counting
algorithms are likely optimal. First,\r\nwe give a lower bound in the \"NP-like\"
black-box query setting: Approximate\r\ncounting requires $\\Omega(\\log n)$ queries,
even on a quantum computer. We then\r\ngive a \"white-box\" lower bound (i.e.
where the input formula is not hidden in\r\nthe oracle) - if there exists a randomized
poly-time classical or quantum\r\nalgorithm for approximate counting making $o(log
n)$ NP queries, then\r\n$\\text{BPP}^{\\text{NP}[o(n)]}$ contains a $\\text{P}^{\\text{NP}}$-complete\r\nproblem
if the algorithm is classical and $\\text{FBQP}^{\\text{NP}[o(n)]}$\r\ncontains
an $\\text{FP}^{\\text{NP}}$-complete problem if the algorithm is\r\nquantum."
author:
- first_name: Sevag
full_name: Gharibian, Sevag
id: '71541'
last_name: Gharibian
orcid: 0000-0002-9992-3379
- first_name: Jonas
full_name: Kamminga, Jonas
last_name: Kamminga
citation:
ama: 'Gharibian S, Kamminga J. BQP, meet NP: Search-to-decision reductions and approximate
counting. In: Proceedings of 51st EATCS International Colloquium on Automata,
Languages and Programming (ICALP). Vol 297. ; 2024:1-19.'
apa: 'Gharibian, S., & Kamminga, J. (2024). BQP, meet NP: Search-to-decision
reductions and approximate counting. Proceedings of 51st EATCS International
Colloquium on Automata, Languages and Programming (ICALP), 297(70),
1–19.'
bibtex: '@inproceedings{Gharibian_Kamminga_2024, title={BQP, meet NP: Search-to-decision
reductions and approximate counting}, volume={297}, number={70}, booktitle={Proceedings
of 51st EATCS International Colloquium on Automata, Languages and Programming
(ICALP)}, author={Gharibian, Sevag and Kamminga, Jonas}, year={2024}, pages={1–19}
}'
chicago: 'Gharibian, Sevag, and Jonas Kamminga. “BQP, Meet NP: Search-to-Decision
Reductions and Approximate Counting.” In Proceedings of 51st EATCS International
Colloquium on Automata, Languages and Programming (ICALP), 297:1–19, 2024.'
ieee: 'S. Gharibian and J. Kamminga, “BQP, meet NP: Search-to-decision reductions
and approximate counting,” in Proceedings of 51st EATCS International Colloquium
on Automata, Languages and Programming (ICALP), 2024, vol. 297, no. 70, pp.
1–19.'
mla: 'Gharibian, Sevag, and Jonas Kamminga. “BQP, Meet NP: Search-to-Decision Reductions
and Approximate Counting.” Proceedings of 51st EATCS International Colloquium
on Automata, Languages and Programming (ICALP), vol. 297, no. 70, 2024, pp.
1–19.'
short: 'S. Gharibian, J. Kamminga, in: Proceedings of 51st EATCS International Colloquium
on Automata, Languages and Programming (ICALP), 2024, pp. 1–19.'
date_created: 2024-01-09T13:59:44Z
date_updated: 2026-05-15T08:41:59Z
department:
- _id: '7'
- _id: '623'
external_id:
arxiv:
- '2401.03943'
intvolume: ' 297'
issue: '70'
language:
- iso: eng
page: 1-19
publication: Proceedings of 51st EATCS International Colloquium on Automata, Languages
and Programming (ICALP)
publication_status: published
status: public
title: 'BQP, meet NP: Search-to-decision reductions and approximate counting'
type: conference
user_id: '71541'
volume: 297
year: '2024'
...
---
_id: '56944'
abstract:
- lang: eng
text: "Quantum Max Cut (QMC), also known as the quantum anti-ferromagnetic\r\nHeisenberg
model, is a QMA-complete problem relevant to quantum many-body\r\nphysics and
computer science. Semidefinite programming relaxations have been\r\nfruitful in
designing theoretical approximation algorithms for QMC, but are\r\ncomputationally
expensive for systems beyond tens of qubits. We give a second\r\norder cone relaxation
for QMC, which optimizes over the set of mutually\r\nconsistent three-qubit reduced
density matrices. In combination with Pauli\r\nlevel-$1$ of the quantum Lasserre
hierarchy, the relaxation achieves an\r\napproximation ratio of $0.526$ to the
ground state energy. Our relaxation is\r\nsolvable on systems with hundreds of
qubits and paves the way to\r\ncomputationally efficient lower and upper bounds
on the ground state energy of\r\nlarge-scale quantum spin systems."
author:
- first_name: Felix
full_name: Huber, Felix
last_name: Huber
- first_name: Kevin
full_name: Thompson, Kevin
last_name: Thompson
- first_name: Ojas
full_name: Parekh, Ojas
last_name: Parekh
- first_name: Sevag
full_name: Gharibian, Sevag
id: '71541'
last_name: Gharibian
orcid: 0000-0002-9992-3379
citation:
ama: Huber F, Thompson K, Parekh O, Gharibian S. Second order cone relaxations for
quantum Max Cut. arXiv:241104120. Published online 2024.
apa: Huber, F., Thompson, K., Parekh, O., & Gharibian, S. (2024). Second order
cone relaxations for quantum Max Cut. In arXiv:2411.04120.
bibtex: '@article{Huber_Thompson_Parekh_Gharibian_2024, title={Second order cone
relaxations for quantum Max Cut}, journal={arXiv:2411.04120}, author={Huber, Felix
and Thompson, Kevin and Parekh, Ojas and Gharibian, Sevag}, year={2024} }'
chicago: Huber, Felix, Kevin Thompson, Ojas Parekh, and Sevag Gharibian. “Second
Order Cone Relaxations for Quantum Max Cut.” ArXiv:2411.04120, 2024.
ieee: F. Huber, K. Thompson, O. Parekh, and S. Gharibian, “Second order cone relaxations
for quantum Max Cut,” arXiv:2411.04120. 2024.
mla: Huber, Felix, et al. “Second Order Cone Relaxations for Quantum Max Cut.” ArXiv:2411.04120,
2024.
short: F. Huber, K. Thompson, O. Parekh, S. Gharibian, ArXiv:2411.04120 (2024).
date_created: 2024-11-07T12:09:37Z
date_updated: 2026-05-15T08:41:38Z
department:
- _id: '7'
- _id: '623'
external_id:
arxiv:
- '2411.04120'
language:
- iso: eng
publication: arXiv:2411.04120
status: public
title: Second order cone relaxations for quantum Max Cut
type: preprint
user_id: '71541'
year: '2024'
...
---
_id: '48544'
abstract:
- lang: eng
text: 'When it comes to NP, its natural definition, its wide applicability across
scientific disciplines, and its timeless relevance, the writing is on the wall:
There can be only one. Quantum NP, on the other hand, is clearly the apple that
fell far from the tree of NP. Two decades since the first definitions of quantum
NP started rolling in, quantum complexity theorists face a stark reality: There''s
QMA, QCMA, QMA1, QMA(2), StoqMA, and NQP. In this article aimed at a general theoretical
computer science audience, I survey these various definitions of quantum NP, their
strengths and weaknesses, and why most of them, for better or worse, actually
appear to fit naturally into the complexity zoo.'
article_type: review
author:
- first_name: Sevag
full_name: Gharibian, Sevag
id: '71541'
last_name: Gharibian
orcid: 0000-0002-9992-3379
citation:
ama: 'Gharibian S. Guest Column: The 7 faces of quantum NP. ACM SIGACT News.
2024;54(4):54-91.'
apa: 'Gharibian, S. (2024). Guest Column: The 7 faces of quantum NP. ACM SIGACT
News, 54(4), 54–91.'
bibtex: '@article{Gharibian_2024, title={Guest Column: The 7 faces of quantum NP},
volume={54}, number={4}, journal={ACM SIGACT News}, author={Gharibian, Sevag},
year={2024}, pages={54–91} }'
chicago: 'Gharibian, Sevag. “Guest Column: The 7 Faces of Quantum NP.” ACM SIGACT
News 54, no. 4 (2024): 54–91.'
ieee: 'S. Gharibian, “Guest Column: The 7 faces of quantum NP,” ACM SIGACT News,
vol. 54, no. 4, pp. 54–91, 2024.'
mla: 'Gharibian, Sevag. “Guest Column: The 7 Faces of Quantum NP.” ACM SIGACT
News, vol. 54, no. 4, 2024, pp. 54–91.'
short: S. Gharibian, ACM SIGACT News 54 (2024) 54–91.
date_created: 2023-10-30T12:19:11Z
date_updated: 2026-05-15T08:42:54Z
department:
- _id: '7'
- _id: '623'
intvolume: ' 54'
issue: '4'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/2310.18010
oa: '1'
page: 54-91
publication: ACM SIGACT News
publication_status: published
related_material:
link:
- relation: confirmation
url: https://dl.acm.org/doi/abs/10.1145/3639528.3639535
status: public
title: 'Guest Column: The 7 faces of quantum NP'
type: journal_article
user_id: '71541'
volume: 54
year: '2024'
...
---
_id: '32407'
abstract:
- lang: eng
text: "Estimating the ground state energy of a local Hamiltonian is a central\r\nproblem
in quantum chemistry. In order to further investigate its complexity\r\nand the
potential of quantum algorithms for quantum chemistry, Gharibian and Le\r\nGall
(STOC 2022) recently introduced the guided local Hamiltonian problem\r\n(GLH),
which is a variant of the local Hamiltonian problem where an\r\napproximation
of a ground state is given as an additional input. Gharibian and\r\nLe Gall showed
quantum advantage (more precisely, BQP-completeness) for GLH\r\nwith $6$-local
Hamiltonians when the guiding vector has overlap\r\n(inverse-polynomially) close
to 1/2 with a ground state. In this paper, we\r\noptimally improve both the locality
and the overlap parameters: we show that\r\nthis quantum advantage (BQP-completeness)
persists even with 2-local\r\nHamiltonians, and even when the guiding vector has
overlap\r\n(inverse-polynomially) close to 1 with a ground state. Moreover, we
show that\r\nthe quantum advantage also holds for 2-local physically motivated
Hamiltonians\r\non a 2D square lattice. This makes a further step towards establishing\r\npractical
quantum advantage in quantum chemistry."
author:
- first_name: Sevag
full_name: Gharibian, Sevag
id: '71541'
last_name: Gharibian
orcid: 0000-0002-9992-3379
- first_name: Ryu
full_name: Hayakawa, Ryu
last_name: Hayakawa
- first_name: François Le
full_name: Gall, François Le
last_name: Gall
- first_name: Tomoyuki
full_name: Morimae, Tomoyuki
last_name: Morimae
citation:
ama: 'Gharibian S, Hayakawa R, Gall FL, Morimae T. Improved Hardness Results for
the Guided Local Hamiltonian Problem. In: Proceedings of the 50th EATCS International
Colloquium on Automata, Languages and Programming (ICALP). Vol 261. ; 2023:1-19.
doi:10.4230/LIPIcs.ICALP.2023.32'
apa: Gharibian, S., Hayakawa, R., Gall, F. L., & Morimae, T. (2023). Improved
Hardness Results for the Guided Local Hamiltonian Problem. Proceedings of the
50th EATCS International Colloquium on Automata, Languages and Programming (ICALP),
261(32), 1–19. https://doi.org/10.4230/LIPIcs.ICALP.2023.32
bibtex: '@inproceedings{Gharibian_Hayakawa_Gall_Morimae_2023, title={Improved Hardness
Results for the Guided Local Hamiltonian Problem}, volume={261}, DOI={10.4230/LIPIcs.ICALP.2023.32},
number={32}, booktitle={Proceedings of the 50th EATCS International Colloquium
on Automata, Languages and Programming (ICALP)}, author={Gharibian, Sevag and
Hayakawa, Ryu and Gall, François Le and Morimae, Tomoyuki}, year={2023}, pages={1–19}
}'
chicago: Gharibian, Sevag, Ryu Hayakawa, François Le Gall, and Tomoyuki Morimae.
“Improved Hardness Results for the Guided Local Hamiltonian Problem.” In Proceedings
of the 50th EATCS International Colloquium on Automata, Languages and Programming
(ICALP), 261:1–19, 2023. https://doi.org/10.4230/LIPIcs.ICALP.2023.32.
ieee: 'S. Gharibian, R. Hayakawa, F. L. Gall, and T. Morimae, “Improved Hardness
Results for the Guided Local Hamiltonian Problem,” in Proceedings of the 50th
EATCS International Colloquium on Automata, Languages and Programming (ICALP),
2023, vol. 261, no. 32, pp. 1–19, doi: 10.4230/LIPIcs.ICALP.2023.32.'
mla: Gharibian, Sevag, et al. “Improved Hardness Results for the Guided Local Hamiltonian
Problem.” Proceedings of the 50th EATCS International Colloquium on Automata,
Languages and Programming (ICALP), vol. 261, no. 32, 2023, pp. 1–19, doi:10.4230/LIPIcs.ICALP.2023.32.
short: 'S. Gharibian, R. Hayakawa, F.L. Gall, T. Morimae, in: Proceedings of the
50th EATCS International Colloquium on Automata, Languages and Programming (ICALP),
2023, pp. 1–19.'
date_created: 2022-07-22T12:32:40Z
date_updated: 2023-10-09T04:17:10Z
department:
- _id: '623'
- _id: '7'
doi: 10.4230/LIPIcs.ICALP.2023.32
external_id:
arxiv:
- '2207.10250'
intvolume: ' 261'
issue: '32'
language:
- iso: eng
page: 1-19
publication: Proceedings of the 50th EATCS International Colloquium on Automata, Languages
and Programming (ICALP)
publication_status: published
status: public
title: Improved Hardness Results for the Guided Local Hamiltonian Problem
type: conference
user_id: '71541'
volume: 261
year: '2023'
...
---
_id: '48502'
abstract:
- lang: eng
text: The prediction of photon echoes is an important technique for gaining an understanding
of optical quantum systems. However, this requires a large number of simulations
with varying parameters and/or input pulses, which renders numerical studies expensive.
This article investigates how we can use data-driven surrogate models based on
the Koopman operator to accelerate this process. In order to be successful, we
require a model that is accurate over a large number of time steps. To this end,
we employ a bilinear Koopman model using extended dynamic mode decomposition and
simulate the optical Bloch equations for an ensemble of inhomogeneously broadened
two-level systems. Such systems are well suited to describe the excitation of
excitonic resonances in semiconductor nanostructures, for example, ensembles of
semiconductor quantum dots. We perform a detailed study on the required number
of system simulations such that the resulting data-driven Koopman model is sufficiently
accurate for a wide range of parameter settings. We analyze the L2 error and the
relative error of the photon echo peak and investigate how the control positions
relate to the stabilization. After proper training, the dynamics of the quantum
ensemble can be predicted accurately and numerically very efficiently by our methods.
author:
- first_name: Sebastian
full_name: Peitz, Sebastian
id: '47427'
last_name: Peitz
orcid: 0000-0002-3389-793X
- first_name: Anna
full_name: Hunstig, Anna
last_name: Hunstig
- first_name: Hendrik
full_name: Rose, Hendrik
id: '55958'
last_name: Rose
orcid: 0000-0002-3079-5428
- first_name: Torsten
full_name: Meier, Torsten
id: '344'
last_name: Meier
orcid: 0000-0001-8864-2072
citation:
ama: Peitz S, Hunstig A, Rose H, Meier T. Accelerating the analysis of optical quantum
systems using the Koopman operator. Published online 2023.
apa: Peitz, S., Hunstig, A., Rose, H., & Meier, T. (2023). Accelerating the
analysis of optical quantum systems using the Koopman operator.
bibtex: '@article{Peitz_Hunstig_Rose_Meier_2023, title={Accelerating the analysis
of optical quantum systems using the Koopman operator}, author={Peitz, Sebastian
and Hunstig, Anna and Rose, Hendrik and Meier, Torsten}, year={2023} }'
chicago: Peitz, Sebastian, Anna Hunstig, Hendrik Rose, and Torsten Meier. “Accelerating
the Analysis of Optical Quantum Systems Using the Koopman Operator,” 2023.
ieee: S. Peitz, A. Hunstig, H. Rose, and T. Meier, “Accelerating the analysis of
optical quantum systems using the Koopman operator.” 2023.
mla: Peitz, Sebastian, et al. Accelerating the Analysis of Optical Quantum Systems
Using the Koopman Operator. 2023.
short: S. Peitz, A. Hunstig, H. Rose, T. Meier, (2023).
date_created: 2023-10-27T09:40:59Z
date_updated: 2023-10-27T10:05:07Z
department:
- _id: '655'
- _id: '623'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/pdf/2310.16578.pdf
oa: '1'
status: public
title: Accelerating the analysis of optical quantum systems using the Koopman operator
type: preprint
user_id: '47427'
year: '2023'
...