I am a theoretical physicist at Princeton University. My interests are in many-body quantum mechanics and the interface between quantum and classical simulation. Here there are connections to be made between statistical mechanics, quantum information, and conventional condensed matter physics.

Recently, a set of problems that I have been focusing on concern the effects that measurements have on many-body quantum systems. These effects are practically relevant to quantum error correction, and to our understanding of the complexity of simulating quantum systems on classical computers. You can find a detailed explanation in this talk (from Simons Center, Berkeley), and an  even more detailed explanation in this talk (from Cornell). 

This summer (2025) I gave a lecture series at Berkeley as part of the NSF Challenge Institute for Quantum Computation (CIQC). There was also a livestream. The course covers the basics of quantum computation, starting from the perspective of quantum dynamics. The target audience is early graduate students in physics and chemistry, and only assumes a familiarity with basic quantum mechanics. Here are the notes.

Preprints

• https://arxiv.org/abs/2504.12385

Learning transitions in classical Ising models and deformed toric codes
Malte Pütz, Samuel J. Garratt, Hidetoshi Nishimori, Simon Trebst, Guo-Yi Zhu

• https://arxiv.org/abs/2502.13218
  Entanglement and private information in many-body thermal states
  Samuel J. Garratt, Max McGinley

• https://arxiv.org/abs/2502.09612
  Superspin renormalization and slow relaxation in random spin systems
  Yi J. Zhao, Samuel J. Garratt, Joel Moore

• https://arxiv.org/abs/2501.09084
  Goldstone mode of the broken helix in U(1) magnet EuIn2As2
  Alex Liebman-Pelaez, Samuel J. Garratt, Veronika Sunko, Yue Sun, Jian R. Soh,  Dharmalingam Prabhakaran, Andrew T. Boothroyd, Joseph Orenstein

• https://arxiv.org/abs/2410.13844

Post-measurement quantum Monte Carlo
Kriti Baweja, David J. Luitz, Samuel J. Garratt

• https://arxiv.org/abs/2407.07893
  Quantum Algorithm to Prepare Quasi-Stationary States
  Samuel J. Garratt, Soonwon Choi

Publications 

• Phys. Rev. B 111, 094316 (2025)
  https://arxiv.org/abs/2312.14234
  Operator dynamics in Floquet many-body systems
  Takato Yoshimura, Samuel J. Garratt, J. T. Chalker

• Phys. Rev. X Quantum 5, 030311 (2024)

https://arxiv.org/abs/2305.20092
Probing post-measurement entanglement without post-selection
Samuel J. Garratt, Ehud Altman

• Phys. Rev. B 107, 245132 (2023) https://arxiv.org/abs/2301.08268
  Nonlocality and entanglement in measured critical quantum Ising chains
  Zack Weinstein, Rohith Sajith, Ehud Altman, Samuel J. Garratt

• Phys. Rev. X 13, 021026 (2023) https://arxiv.org/abs/2207.09476
  Measurements conspire nonlocally to restructure critical quantum states
  Samuel J. Garratt, Zack Weinstein, Ehud Altman

• Phys. Rev. B 106, 054309 (2022) https://arxiv.org/abs/2202.10482
  Resonant energy scales and local observables in the many-body localized phase
  Samuel J. Garratt, Sthitadhi Roy

• Phys. Rev. A 106, 012441 (2022) https://arxiv.org/abs/2202.05132 

Quantifying information scrambling via Classical Shadow Tomography on Programmable Quantum Simulators

Max McGinley, Sebastian Leontica, Samuel J. Garratt, Jovan Jovanovic, Steven H. Simon

• Phys. Rev. B 104, 184203 (2021) https://arxiv.org/abs/2107.12387
  Local resonances and parametric level dynamics in the many-body localised phase
  S. J Garratt, Sthitadhi Roy, J. T. Chalker

• Phys. Rev. Lett. 127, 026802 (2021) https://arxiv.org/abs/2012.11580
  Many-body delocalisation as symmetry breaking
  S. J Garratt, J. T. Chalker

• Phys. Rev. X 11, 021051 (2021) https://arxiv.org/abs/2008.01697
  Local pairing of Feynman histories in many-body Floquet models
  S. J. Garratt, J. T. Chalker

• Phys. Rev. Lett. 126, 060402 https://arxiv.org/abs/2004.11363
  Many-body Decay of the Gapped Lowest Excitation of a Bose-Einstein Condensate
  Jinyi Zhang, Christoph Eigen, Wei Zheng, Jake A. P. Glidden, Timon A. Hilker, Samuel J. Garratt, Raphael Lopes, Nigel R. Cooper, Zoran Hadzibabic, Nir Navon

• Phys. Rev. B 101, 024413 (2020) https://arxiv.org/abs/1908.02271
  Goldstone modes in the emergent gauge fields of a frustrated magnet
  Samuel J. Garratt, J. T. Chalker

• Phys. Rev. A 99, 021601(R) (2019) https://arxiv.org/abs/1810.08195
  From single-particle excitations to sound waves in a box-trapped atomic Bose-Einstein condensate
  Samuel J. Garratt, Christoph Eigen, Jinyi Zhang, Patrik Turzák, Raphael Lopes, Robert P. Smith, Zoran Hadzibabic, Nir Navon

Research & before

• 2025 - now: Associate Research Scholar in Princeton 

• 2021 - 2025: Moore Fellowship in Berkeley, working with Ehud Altman and Joel Moore.

• 2017 - 2021: DPhil from Oxford, working with John Chalker. 

• 2013 - 2017: BA + MSci from Cambridge, with research in the group of Zoran Hadzibabic.