Next-generation quantum devices and sensors—spanning nanoscale electronics, quantum-dot platforms, and solid-state spin systems—depend on precise understanding and control of coherence, dissipation, and measurement back-action. Theory and computation are central to this effort, but classical simulation is challenging: the many-body Hilbert space grows exponentially, and open-system dynamics introduce additional structure, approximations, and error modes that must be understood and controlled.

Our research develops computational frameworks, scalable algorithms, and physical principles for efficient classical simulation of complex open quantum systems, with an emphasis on nonequilibrium quantum transport and measurement-driven dynamics relevant to sensing and control. We combine pen-and-paper theory with open-system modeling (e.g., Lindblad/relaxation approaches), tensor-network methods (MPS/MPO), and high-performance scientific computing. A core thrust is the extended reservoir approach (ERA) for nonequilibrium quantum transport—an open-system simulation framework with clear stability criteria and quantitative routes to continuum-limit recovery and error control. We maintain a close connection to experimentally motivated questions and device-relevant observables (currents, spectra, noise, and estimation performance).

Example research directions (not exhaustive)

• Nonequilibrium quantum transport with dissipation/relaxation: the extended reservoir approach (ERA), continuum-limit recovery, stability criteria, and quantitative error control for steady states and driven (Floquet) settings.
• Tensor-network methods for transport and open systems: efficient representations and time-evolution strategies that break computational bottlenecks for long-time or large-system simulations (including algorithmic advances and diagnostics for convergence/accuracy).
• Measurement, inference, and emergence of classicality: how information becomes redundant in realistic environments; connections to sensing platforms (e.g., solid-state spins) and to principled bounds on what measurements can reveal.
• Algorithm/software development for large-scale simulations: performance engineering, numerical linear algebra, verification/validation, and reproducible scientific workflows.

Desired background/skills

We seek candidates with deep expertise in one or more of: many-body quantum physics; open quantum systems; nonequilibrium/statistical physics; quantum information; tensor networks; and/or computational physics. Strong scientific programming skills (Python/C/C++), experience with numerical linear algebra, and comfort working on HPC systems are highly valued. Candidates who enjoy translating physical insight into robust algorithms—and stress-testing those algorithms with careful diagnostics—will be especially successful.

How to apply / contact

Prospective applicants are encouraged to email a short note describing technical fit and interests, along with a CV, to: mpz@nist.gov

Group overview: Biophysical and Biomedical Measurement Group

References (selected)

• Approaching the scaling limit of transport through lattices with dephasing, S. Sarkar, G. Wójtowicz, B. Gardas, M. M. Rams, & M. Zwolak, The Journal of Chemical Physics 163, 114101 (2025)
• Confluence of fractured resonances at points of dynamical many-body flare, B. De, G. Wójtowicz, M. M. Rams, M. Zwolak, & J. Zakrzewski, Physical Review B 110, 155146 (2024)
• Transport in a periodically driven tilted lattice via the extended reservoir approach: Stability criterion for recovering the continuum limit, B. De, G. Wójtowicz, J. Zakrzewski, M. Zwolak, & M. M. Rams, Physical Review B 107, 235148 (2023)
• Accumulative reservoir construction: Bridging continuously relaxed and periodically refreshed extended reservoirs, G. Wójtowicz, A. Purkayastha, M. Zwolak, & M. M. Rams, Physical Review B 107, 035150 (2023)
• Amplification, inference, and the manifestation of objective classical information, M. Zwolak, Entropy 24, 781 (2022)
• Dual current anomalies and quantum transport within extended reservoir simulations, G. Wójtowicz, J. E. Elenewski, M. M. Rams, & M. Zwolak, Physical Review B 104, 165131 (2021)
• Performance of reservoir discretizations in quantum transport simulations, J. E. Elenewski, G. Wójtowicz, M. M. Rams, & M. Zwolak, The Journal of Chemical Physics 155, 124117 (2021)
• Analytic expressions for the steady-state current with finite extended reservoirs, M. Zwolak, The Journal of Chemical Physics 153, 224107 (2020)
• Open-system tensor networks and Kramers’ crossover for quantum transport, G. Wójtowicz, J. E. Elenewski, M. M. Rams, & M. Zwolak, Physical Review A 101, 050301(R) (2020)
• Revealing the emergence of classicality in nitrogen-vacancy centers, T. Unden, D. Louzon, M. Zwolak, W. H. Zurek, & F. Jelezko, Physical Review Letters 123, 140402 (2019)
• Breaking the entanglement barrier: Tensor network simulation of quantum transport, M. M. Rams & M. Zwolak, Physical Review Letters 124, 137701 (2020)

Open quantum systems; nonequilibrium quantum transport; quantum simulation; tensor networks; matrix product states; matrix product operators; Lindblad/master-equation methods; extended reservoirs; dephasing and relaxation; continuum limit; Floquet/periodically driven transport; quantum dots and nanoscale devices; quantum sensing; decoherence; measurement back-action; inference; emergent classicality; numerical linear algebra; algorithm development; high-performance computing; reproducible research

citizenship

Open to U.S. citizens

level

Open to Postdoctoral applicants