Rubidium Lab


Postdocs


Graduate Students


Former Group Members

Joyce Kwan

Graduate Student (2018-2025)

Brice Bakkali-Hassani

Postdoc (2022-2024)

Sooshin Kim

Graduate Student (2017-2023)

Julian Léonard

Postdoc (2017-2021)

Robert Schittko

Graduate Student (2015-2021)

Alex Lukin

Graduate Student (2012-2018)

Matthew Rispoli

Graduate Student (2013-2019)

Eric Tai

Graduate Student (2009-2017)

Adam Kaufman

Postdoc (2015-2017)

Tim Menke

Graduate Student (2016-2017)

Philipp Preiss

Graduate Student (2010-2015)

Rajibul Islam

Postdoc (2012-2015)

Ruichao Ma

Graduate Student (2009-2014)

Philip Zupancic

Visiting Student (2012-2013)

Jonathan Simon

Postdoc (2010-2012)

Waseem Bakr

Graduate Student (2006-2011)

Johannes Brachmann

Diploma/Master’s Student

Peter Unterwaditzer

Diploma/Master’s Student

Simon Fölling

Postdoc (200x-2010)

Amy Peng

Graduate Student (200x-2010)

Jonathon Gillen

Graduate Student (200x-2009)

Ultracold atomic systems can be used as quantum simulators to study a range of phenomena in strongly-correlated materials ranging from high-Tc superconductors to quantum magnets. The micron-scale spacing of atoms in these systems provides an opportunity to optically image fluctuations and correlations in strongly correlated systems in a way not possible in condensed matter. Our quantum gas microscopy (QGM) allows, for the first time, for optical imaging and manipulation of strongly-interacting quantum gases containing thousands of atoms at the single atom level. The ideas introduced in QGM are quite general and can be applied to a range of other systems including fermionic (See our Fermi Gas Microscope experiment) and dipolar gases (See our planned Erbium QGM). In addition, it provides a path to quantum computation in a system with a scalable architecture.


A Pfaffian quantum Hall state of ultracold bosons
07/2026
arXiv:2606.12409
J. Kwan*, P. Segura*, Y. Li, Tizian Blatz, A. Zhi, B. Bakkali-Hassani, Annabelle Bohrdt, Martin Greiter, Fabian Grusdt, M. Greiner

Fractional quantum Hall states are a cornerstone of topological physics, hosting fractionally charged quasiparticles with exotic statistics that promise to enable topologically protected quantum information processing. Among these, the Pfaffian state introduced by Moore and Read implements a p-wave pairing structure that supports excitations with non-Abelian exchange statistics. Despite extensive study in electronic systems, direct access to its pairing structure has remained limited. Here we realize a three-particle bosonic Pfaffian state of ultracold 87Rb atoms in an optical lattice subject to a Floquet-engineered synthetic magnetic field. Using a Bayesian-optimized adiabatic protocol, we prepare a state exhibiting Pfaffian pairing correlations. Site-resolved measurements of multi-point density correlations reveal a pronounced suppression of short-range three-body coincidences, reflecting the underlying pairing structure. We further probe the state’s transport response through Hall drift measurements. Our results establish a bottom-up approach to engineering non-Abelian topological order and lay the groundwork for future explorations of anyonic braiding in synthetic matter.

Revealing Pseudo-Fermionization and Chiral Binding of One-Dimensional Anyons using Adiabatic State Preparation
02/2026
arXiv:2602.20421
B. Bakkali-Hassani, J. Kwan, P. Segura, Y. Li, Isaac Tesfaye, Gerard Valení-Rojas, André Eckardt, M. Greiner

Fractional statistics give rise to quantum behaviors that differ fundamentally from those of bosons and fermions. While two-dimensional anyons play a major role in strongly correlated systems and topological quantum computing, the nature of their one-dimensional (1D) counterparts remains the subject of intense debate, with renewed interest fueled by recent experimental progress. Theoretically, 1D anyons are predicted to host exotic many-body phases and quantum phase transitions, yet experimental signatures have remained elusive. Using ultracold atoms in an optical lattice, we prepare two-body ground states of the 1D anyon-Hubbard model by combining Hamiltonian engineering via quasiperiodic drives and adiabatic state manipulation. We uncover the effects of statistical interactions that lead to pseudo-fermionization and to the formation of chiral bound states when particles remain close together. Our results establish a link between lattice and continuum realizations of anyon models, and mark important steps towards the precise control of 1D anyons in both equilibrium and out-of-equilibrium settings.

Multi-Particle Quantum Walks in a Dipole-Conserving Bose-Hubbard Model
11/2025
arXiv:2511.02343
S. Kim, Byungmin Kang, P. Segura, Y. Li, Ethan Lake, B. Bakkali-Hassani, M. Greiner

When particles move through a crystal or optical lattice, their motion can sometimes become frozen by strong external forces – yet collective motion may still emerge through subtle many-body effects. In this work, we explore such constrained dynamics by realizing a dipole-conserving Bose-Hubbard model, where single atoms are immobile but pairs of particles can move cooperatively while preserving the system’s center of mass, i.e. the overall dipole moment of the particle distribution. Starting from a one-dimensional chain of ultracold bosonic atoms in an optical lattice, we generate localized dipole excitations consisting of a hole and a doublon using site-resolved optical potentials and characterize their quantum walks and scattering dynamics. Our study provides a bottom-up investigation of a Hamiltonian with kinetic constraints, and paves the way for exploring low-energy phases of fractonic matter in existing experimental platforms.

Realization of 1D Anyons with Arbitrary Statistical Phase
11/2024
Science 386,1055-1060 (2024)
J. Kwan, P. Segura, Y. Li, S. Kim, Alexey V. Gorshkov, André Eckardt, B. Bakkali-Hassani, M. Greiner

Low-dimensional quantum systems can host anyons, particles with exchange statistics that are neither bosonic nor fermionic. Despite indications of a wealth of exotic phenomena, the physics of anyons in one dimension (1D) remains largely unexplored. Here, we realize Abelian anyons in 1D with arbitrary exchange statistics using ultracold atoms in an optical lattice, where we engineer the statistical phase via a density-dependent Peierls phase. We explore the dynamical behavior of two anyons undergoing quantum walks, and observe the anyonic Hanbury Brown-Twiss effect, as well as the formation of bound states without on-site interactions. Once interactions are introduced, we observe spatially asymmetric transport in contrast to the symmetric dynamics of bosons and fermions. Our work forms the foundation for exploring the many-body behavior of 1D anyons.

Adiabatic State Preparation in a Quantum Ising Spin Chain
04/2024
arXiv:2404.07481
We report on adiabatic state preparation in the one-dimensional quantum Ising model using ultracold bosons in a tilted optical lattice. We prepare many-body ground states of controllable system sizes and observe enhanced fluctuations around the transition between paramagnetic and antiferromagnetic states, marking the precursor of quantum critical behavior. Furthermore, we find evidence for superpositions of domain walls and study their effect on the many-body ground state by measuring the populations of each spin configuration across the transition. These results shed new light on the effect of boundary conditions in finite-size quantum systems.