Lecturer:  Nir Bar-Gill, Applied Physics and Physics, The Hebrew University

Abstract:
The study of open quantum systems, quantum thermodynamics and quantum many-body
spin physics in realistic solid-state systems, has been a long-standing goal in quantum and
condensed-matter physics.
In this talk I will address these topics through the platform of nitrogen-vacancy (NV) spins in
diamond, which have emerged over the past several years as well-controlled quantum
systems, with promising applications ranging from quantum information science to magnetic
sensing. I will first briefly introduce the NV center system, as well as the experimental
methods used for measuring NVs and controlling their quantum spin dynamics. I will then
detail our work in the context of bath characterization and control as a quantum resource
and for enhanced metrology and sensing.
I will describe our research on characterizing noise using robust techniques for quantum
control ([1], in collaboration with Ra’am Uzdin). This approach suppresses sensitivity to
coherent errors while enabling noise characterization, providing a useful tool for the study
of complicated open quantum systems, with the potential for contributions to enhanced
sensing. I will then present a general theoretical framework we developed for Hamiltonian
engineering in an interacting spin system [2]. This framework is applied to the coupling of
the spin ensemble to a spin bath, including both coherent and dissipative dynamics [3].
Using these tools, I will present our recent results on enhanced coherence in many-body
spin systems, surpassing the current state-of-the-art and providing a path toward studies of
disordered many-body spin problems and applications in quantum technologies, such as
enhanced sensing [4].
Finally, if time permits, I will describe our work in using NV-based magnetic microscopy to
implement quantum sensing in various modalities. Demonstrations of NV sensing
capabilities will include measurements of 2D vdW magnetic materials [5], novel hybrid NV-
atomic vapor vector magnetic sensing [6], and sensing in biological scenarios [7,8].

1. P. PENSHIN ET. AL., AVS QUANTUM SCI. 6, 025002 (2024).
2. K. I. O. BEN’ATTAR, D. FARFURNIK AND N. BAR-GILL, PHYS. REV. RESEARCH 2, 013061 (2020).
3. K. I. O. BEN’ATTAR ET. AL., IN PREPARATION.
4. A. ABRAMOVICH ET. AL., IN PREPARATION.
5. B. BINDU ET. AL., IN PREPARATION.
6. I. SHALEV ET. AL., SUBMITTED,
7. Y. NINIO ET. AL., ACS PHOTONICS 8, 7, 1917-1921 (2021).
8. T. AMRO ET. AL., IN PREPARATION.