@article{61266,
  abstract     = {{<jats:p>This review examines the use of continuous-variable spectroscopy techniques for investigating quantum coherence and light-matter interactions in semiconductor systems with ultrafast dynamics. Special emphasis is placed on multichannel homodyne detection as a powerful tool to measure the quantum coherence and the full density matrix of a polariton system. Observations, such as coherence times that exceed the nanosecond scale obtained by monitoring the temporal decay of quantum coherence in a polariton condensate, are discussed. Proof-of-concept experiments and numerical simulations that demonstrate the enhanced resourcefulness of the produced system states for modern quantum protocols are assessed. The combination of tailored resource quantifiers and ultrafast spectroscopy techniques that have recently been demonstrated paves the way for future applications of quantum information technologies.</jats:p>}},
  author       = {{Lüders, Carolin and Barkhausen, Franziska and Pukrop, Matthias and Rozas, Elena and Sperling, Jan and Schumacher, Stefan and Aßmann, Marc}},
  issn         = {{2159-3930}},
  journal      = {{Optical Materials Express}},
  number       = {{11}},
  publisher    = {{Optica Publishing Group}},
  title        = {{{Continuous-variable quantum optics and resource theory for ultrafast semiconductor spectroscopy [Invited]}}},
  doi          = {{10.1364/ome.497006}},
  volume       = {{13}},
  year         = {{2023}},
}

@inproceedings{43744,
  abstract     = {{We demonstrate theoretically and experimentally complex correlations in the photon numbers of two-mode quantum states using measurement-induced nonlinearity. For this, we combine the interference of coherent states and single photons with photon sub-traction.}},
  author       = {{Meier, Torsten and Hoepker, Jan Philipp and Protte, Maximilian and Eigner, Christof and Silberhorn, Christine and Sharapova, Polina R. and Sperling, Jan and Bartley, Tim}},
  booktitle    = {{Conference on Lasers and Electro-Optics: Applications and Technology}},
  isbn         = {{978-1-957171-05-0}},
  location     = {{San Jose, California United States}},
  pages        = {{JTu3A. 17}},
  publisher    = {{Optica Publishing Group}},
  title        = {{{Two-Mode Photon-Number Correlations Created by Measurement-Induced Nonlinearity}}},
  doi          = {{10.1364/CLEO_AT.2022.JTu3A.17}},
  year         = {{2022}},
}

@article{34884,
  author       = {{Prasannan, Nidhin and Sperling, Jan and Brecht, Benjamin and Silberhorn, Christine}},
  issn         = {{0031-9007}},
  journal      = {{Physical Review Letters}},
  keywords     = {{General Physics and Astronomy}},
  number       = {{26}},
  publisher    = {{American Physical Society (APS)}},
  title        = {{{Direct Measurement of Higher-Order Nonlinear Polarization Squeezing}}},
  doi          = {{10.1103/physrevlett.129.263601}},
  volume       = {{129}},
  year         = {{2022}},
}

@article{30921,
  abstract     = {{Quantum walks function as essential means to implement quantum simulators, allowing one to study complex and often directly inaccessible quantum processes in controllable systems. In this contribution, the notion of a driven Gaussian quantum walk is introduced. In contrast to typically considered quantum walks in optical settings, we describe the operation of the walk in terms of a nonlinear map rather than a unitary operation, e.g., by replacing a beam-splitter-type coin with a two-mode squeezer, being a process that is controlled and driven by a pump field. This opens previously unattainable possibilities for quantum walks that include nonlinear elements as core components of their operation, vastly extending their range of applications. A full framework for driven Gaussian quantum walks is developed, including methods to dynamically characterize nonlinear, quantum, and quantum-nonlinear effects. Moreover, driven Gaussian quantum walks are compared with their classically interfering and linear counterparts, which are based on classical coherence of light rather than quantum superpositions. In particular, the generation and boost of highly multimode entanglement, squeezing, and other quantum effects are studied over the duration of the nonlinear walk. Importantly, we prove the quantumness of the evolution itself, regardless of the input state. A scheme for an experimental realization is proposed. Furthermore, nonlinear properties of driven Gaussian quantum walks are explored, such as amplification that leads to an ever increasing number of correlated quantum particles, constituting a source of new walkers during the walk. Therefore, a concept for quantum walks is proposed that leads to—and even produces—directly accessible quantum phenomena, and that renders the quantum simulation of nonlinear processes possible.}},
  author       = {{Held, Philip and Engelkemeier, Melanie and De, Syamsundar and Barkhofen, Sonja and Sperling, Jan and Silberhorn, Christine}},
  issn         = {{2469-9926}},
  journal      = {{Physical Review A}},
  number       = {{4}},
  publisher    = {{American Physical Society (APS)}},
  title        = {{{Driven Gaussian quantum walks}}},
  doi          = {{10.1103/physreva.105.042210}},
  volume       = {{105}},
  year         = {{2022}},
}

@article{26889,
  author       = {{Luo, Kai Hong and Santandrea, Matteo and Stefszky, Michael and Sperling, Jan and Massaro, Marcello and Ferreri, Alessandro and Sharapova, Polina and Herrmann, Harald and Silberhorn, Christine}},
  issn         = {{2469-9926}},
  journal      = {{Physical Review A}},
  title        = {{{Quantum optical coherence: From linear to nonlinear interferometers}}},
  doi          = {{10.1103/physreva.104.043707}},
  year         = {{2021}},
}

@article{26283,
  author       = {{Lüders, Carolin and Pukrop, Matthias and Rozas, Elena and Schneider, Christian and Höfling, Sven and Sperling, Jan and Schumacher, Stefan and Aßmann, Marc}},
  issn         = {{2691-3399}},
  journal      = {{PRX Quantum}},
  title        = {{{Quantifying Quantum Coherence in Polariton Condensates}}},
  doi          = {{10.1103/prxquantum.2.030320}},
  year         = {{2021}},
}

@article{26284,
  author       = {{Bagrets, Dmitry and Kim, Kun Woo and Barkhofen, Sonja and De, Syamsundar and Sperling, Jan and Silberhorn, Christine and Altland, Alexander and Micklitz, Tobias}},
  issn         = {{2643-1564}},
  journal      = {{Physical Review Research}},
  title        = {{{Probing the topological Anderson transition with quantum walks}}},
  doi          = {{10.1103/physrevresearch.3.023183}},
  year         = {{2021}},
}

@article{26287,
  author       = {{Geraldi, Andrea and De, Syamsundar and Laneve, Alessandro and Barkhofen, Sonja and Sperling, Jan and Mataloni, Paolo and Silberhorn, Christine}},
  issn         = {{2643-1564}},
  journal      = {{Physical Review Research}},
  title        = {{{Transient subdiffusion via disordered quantum walks}}},
  doi          = {{10.1103/physrevresearch.3.023052}},
  year         = {{2021}},
}

@article{21021,
  author       = {{Tiedau, J. and Engelkemeier, M. and Brecht, Benjamin and Sperling, Jan and Silberhorn, Christine}},
  issn         = {{0031-9007}},
  journal      = {{Physical Review Letters}},
  title        = {{{Statistical Benchmarking of Scalable Photonic Quantum Systems}}},
  doi          = {{10.1103/physrevlett.126.023601}},
  volume       = {{126}},
  year         = {{2021}},
}

@article{26286,
  author       = {{Prasannan, Nidhin and De, Syamsundar and Barkhofen, Sonja and Brecht, Benjamin and Silberhorn, Christine and Sperling, Jan}},
  issn         = {{2469-9926}},
  journal      = {{Physical Review A}},
  title        = {{{Experimental entanglement characterization of two-rebit states}}},
  doi          = {{10.1103/physreva.103.l040402}},
  volume       = {{103}},
  year         = {{2021}},
}

@article{26285,
  author       = {{Köhnke, S. and Agudelo, E. and Schünemann, M. and Schlettwein, O. and Vogel, W. and Sperling, Jan and Hage, B.}},
  issn         = {{0031-9007}},
  journal      = {{Physical Review Letters}},
  title        = {{{Quantum Correlations beyond Entanglement and Discord}}},
  doi          = {{10.1103/physrevlett.126.170404}},
  year         = {{2021}},
}

@article{26294,
  author       = {{Sperling, Jan and Phillips, D. S. and Bulmer, J. F. F and Thekkadath, G. S. and Eckstein, A. and Wolterink, T. A. W. and Lugani, J. and Nam, S. W. and Lita, A. and Gerrits, T. and Vogel, W. and Agarwal, G. S. and Silberhorn, Christine and Walmsley, I. A.}},
  issn         = {{0031-9007}},
  journal      = {{Physical Review Letters}},
  title        = {{{Detector-Agnostic Phase-Space Distributions}}},
  doi          = {{10.1103/physrevlett.124.013605}},
  year         = {{2020}},
}

@article{21023,
  author       = {{Engelkemeier, M. and Lorz, L. and De, Syamsundar and Brecht, Benjamin and Dhand, I. and Plenio, M. B. and Silberhorn, Christine and Sperling, Jan}},
  issn         = {{2469-9926}},
  journal      = {{Physical Review A}},
  title        = {{{Quantum photonics with active feedback loops}}},
  doi          = {{10.1103/physreva.102.023712}},
  volume       = {{102}},
  year         = {{2020}},
}

@article{26289,
  author       = {{Nitsche, Thomas and De, Syamsundar and Barkhofen, Sonja and Meyer-Scott, Evan and Tiedau, Johannes and Sperling, Jan and Gábris, Aurél and Jex, Igor and Silberhorn, Christine}},
  issn         = {{0031-9007}},
  journal      = {{Physical Review Letters}},
  title        = {{{Local Versus Global Two-Photon Interference in Quantum Networks}}},
  doi          = {{10.1103/physrevlett.125.213604}},
  year         = {{2020}},
}

@article{26290,
  abstract     = {{<jats:p>We devise a method to certify nonclassical features via correlations of phase-space distributions by unifying the notions of quasiprobabilities and matrices of correlation functions. Our approach complements and extends recent results that were based on Chebyshev's integral inequality \cite{BA19}. The method developed here correlates arbitrary phase-space functions at arbitrary points in phase space, including multimode scenarios and higher-order correlations. Furthermore, our approach provides necessary and sufficient nonclassicality criteria, applies to phase-space functions beyond <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>s</mml:mi></mml:math>-parametrized ones, and is accessible in experiments. To demonstrate the power of our technique, the quantum characteristics of discrete- and continuous-variable, single- and multimode, as well as pure and mixed states are certified only employing second-order correlations and Husimi functions, which always resemble a classical probability distribution. Moreover, nonlinear generalizations of our approach are studied. Therefore, a versatile and broadly applicable framework is devised to uncover quantum properties in terms of matrices of phase-space distributions.</jats:p>}},
  author       = {{Bohmann, Martin and Agudelo, Elizabeth and Sperling, Jan}},
  issn         = {{2521-327X}},
  journal      = {{Quantum}},
  title        = {{{Probing nonclassicality with matrices of phase-space distributions}}},
  doi          = {{10.22331/q-2020-10-15-343}},
  year         = {{2020}},
}

@article{26292,
  author       = {{Sperling, Jan and Walmsley, I A}},
  issn         = {{0031-8949}},
  journal      = {{Physica Scripta}},
  title        = {{{Classical evolution in quantum systems}}},
  doi          = {{10.1088/1402-4896/ab833b}},
  year         = {{2020}},
}

@article{26293,
  author       = {{Sperling, Jan and Vogel, W}},
  issn         = {{0031-8949}},
  journal      = {{Physica Scripta}},
  title        = {{{Quasiprobability distributions for quantum-optical coherence and beyond}}},
  doi          = {{10.1088/1402-4896/ab5501}},
  year         = {{2019}},
}

@article{26297,
  author       = {{Cimini, Valeria and Gianani, Ilaria and Sbroscia, Marco and Sperling, Jan and Barbieri, Marco}},
  issn         = {{2643-1564}},
  journal      = {{Physical Review Research}},
  title        = {{{Measuring coherence of quantum measurements}}},
  doi          = {{10.1103/physrevresearch.1.033020}},
  year         = {{2019}},
}

@article{26298,
  author       = {{Rezai, Mohammad and Sperling, Jan and Gerhardt, Ilja}},
  issn         = {{2058-9565}},
  journal      = {{Quantum Science and Technology}},
  title        = {{{What can single photons do what lasers cannot do?}}},
  doi          = {{10.1088/2058-9565/ab3d56}},
  year         = {{2019}},
}

@article{26299,
  author       = {{Phillips, D. S. and Walschaers, M. and Renema, J. J. and Walmsley, I. A. and Treps, N. and Sperling, Jan}},
  issn         = {{2469-9926}},
  journal      = {{Physical Review A}},
  title        = {{{Benchmarking of Gaussian boson sampling using two-point correlators}}},
  doi          = {{10.1103/physreva.99.023836}},
  year         = {{2019}},
}