Observation of many-body localization of interacting fermions in a quasirandom optical lattice

By Michael Schreiber, S. Hodgman, P. Bordia, H. Lüschen, Mark H. Fischer, Ronen Vosk, E. Altman, U. Schneider, I. Bloch. Science, 2015

1,582 citations recorded by the source corpus.

Making interacting atoms localize Disorder can stop the transport of noninteracting particles in its tracks. This phenomenon, known as Anderson localization, occurs in disordered solids, as well as photonic and cold atom settings. Interactions tend to make localization less likely, but disorder, interactions, and localization may coexist in the so-called many-body localized state. Schreiber et al. detect many-body localization in a one-dimensional optical lattice initially filled with atoms occupying alternating sites. Externally induced disorder and interactions prevented the system from evolving quickly to a state with a single atom on each site. Science, this issue p. 842 Disorder and interactions are tuned to induce nonergodic behavior in an atomic system in a one-dimensional optical lattice. Many-body localization (MBL), the disorder-induced localization of interacting particles, signals a breakdown of conventional thermodynamics because MBL systems do not thermalize and show nonergodic time evolution. We experimentally observed this nonergodic evolution for interacting fermions in a one-dimensional quasirandom optical lattice and identified the MBL transition through the relaxation dynamics of an initially prepared charge density wave. For sufficiently weak disorder, the time evolution appears ergodic and thermalizing, erasing all initial ordering, whereas above a critical disorder strength, a substantial portion of the initial ordering persists. The critical disorder value shows a distinctive dependence on the interaction strength, which is in agreement with numerical simulations. Our experiment paves the way to further detailed studies of MBL, such as in noncorrelated disorder or higher dimensions.

Subfields: Artificial Intelligence, Atomic and Molecular Physics, and Optics

View Paper: https://www.semanticscholar.org/paper/00d9a066244ce6d134e2809bc679a5864cb2de17

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In Artificial Intelligence

1. A. Nahum
2. Matthew Fisher
3. V. Khemani
4. Yuan Su
5. S. Vijay
6. M. Fishman
7. S. Gopalakrishnan
8. V. Ros

In Atomic and Molecular Physics, and Optics

1. V. Khemani
2. A. Nahum
3. D. Abanin
4. Matthew Fisher
5. Maksym Serbyn
6. J. Imbrie
7. V. Ros
8. Romain Vasseur

Citations in the corpus

• Superfluidity in nuclear systems and neutron stars (2018, background): “By placing fermions in an optical lattice of suitable design, one is now able to simulate the effect of a periodic potential on the properties of strongly correlated fermions subject to tunable interactions (Bloch, 2004; Chin et al., 2006; Schreiber et al., 2015; Zwerger, 2003).”
• Quantum certification and benchmarking (2019, background): “This approach is particularly prominent in quantum simulation: Here, the idea is to certify a quantum device by validating its correct functioning in certain classically simulable regimes through comparison to classical simulations [17, 84, 93, 94].”
• Quantum simulation of the Hubbard model with ultracold fermions in optical lattices (2018, neutral): “Finally, other promising directions for future research include the study of out-of-equilibrium dynamics in this system [174,111,175,176], and the interplay of strong correlations with disorder [81,177,178] and topology [179–182].”
• Signatures of Many-Body Localization in a Controlled Open Quantum System (2016, methodology): “2 nm) disorder lattice to implement the interactingAubry-Andrémodel [13,38] in the individual tubes.”
• The ITensor Software Library for Tensor Network Calculations (2020, background): “[57], obtaining good agreement with experimental observations of the difference between the number of atoms in even versus odd minima of the external potential.”
• Many-body localization and delocalization in large quantum chains (2018, background): “In this context, it is interesting to note that a similar slow transport near the transition (or, more accurately, apparent transition) is also found for quasiperiodic systems [13] as well as in two-dimensional disordered systems [75], where the influence of rare bottlenecks is expected to be neglig”
• Aspects of non-equilibrium in classical and quantum systems: Slow relaxation and glasses, dynamical large deviations, quantum non-ergodicity, and open quantum dynamics (2017, background): “lled a charge density wave. A simple observable which quanties the extent to which the system remembers the initial patter is the dierence in density between even and odd sites, or \imbalance" [91], I(t) = N o(t) N e(t) N o(t) + N e(t) : (57) 13 Figure 7: Slow quantum relaxation due to constrai”
• Local integrals of motion in many‐body localized systems (2016, background): “More recently, there are claims of experimental observations of MBL in artificial quantum systems of cold atoms [21, 29, 91] or trapped ions [96].”