Quantum 2-SAT on low dimensional systems is $\'6dathsfQMA_1$-complete:  Direct embeddings and black-box simulation
D. Rudolph, S. Gharibian, D. Nagaj, ArXiv:2401.02368 (2024).

Quantum Polynomial Hierarchies: Karp-Lipton, error reduction, and lower  bounds
A. Agarwal, S. Gharibian, V. Koppula, D. Rudolph, ArXiv:2401.01633 (2024).