Bulletin of the American Physical Society
APS March Meeting 2023
Volume 68, Number 3
Las Vegas, Nevada (March 5-10)
Virtual (March 20-22); Time Zone: Pacific Time
Session A66: Disorder and Localization in AMO SystemsFocus
|
Hide Abstracts |
Sponsoring Units: DAMOP Chair: Cristian Bahrim, Lamar University Room: Room 413 |
Monday, March 6, 2023 8:00AM - 8:36AM |
A66.00001: Many-body Dynamical Delocalization and Many-body Anderson Metal-Insulator Transition with Kicked Ultracold Quantum Gases Invited Speaker: Subhadeep Gupta Understanding the interplay of interactions and disorder in quantum transport poses long-standing fundamental challenges for both theory and experiment. We utilize a synthetic momentum lattice platform using ultracold quantum gases kicked by pulsed optical lattices, to experimentally investigate this problem. Using periodic kicks, we simulate the 1D Anderson model in momentum-space and observe the interaction-driven emergence of dynamical delocalization and many-body quantum chaos [1]. The observed dynamics feature sub-diffusive energy growth and sheds light on the evolution of dynamically localized states in the presence of many-body interactions, which has long remained an open question. Using quasi-periodic kicks, we experimentally investigate the role of many-body interactions in the 3D Anderson metal-insulator transition. We observe and characterize interaction-driven delocalization of a non-universal sub-diffusive nature in the insulator regime of the non-interacting phase diagram, corresponding to an interaction-induced shift of the metal-insulator transition boundary [2]. Our results shed light on interaction-driven transport phenomena in quantum many-body systems, in a regime where theoretical approaches are extremely challenging and provide conflicting predictions. |
Monday, March 6, 2023 8:36AM - 8:48AM |
A66.00002: Coherent control of localization in phase-modulated quasiperiodic lattices Yifei Bai, Toshihiko Shimasaki, Hasan Kondakci, Max Prichard, Jared E Pagett, Peter Dotti, David M Weld We report experiments demonstrating reversible coherent control of a localization phase transition by phasonic modulation. As background, we recently reported phasonic spectroscopy of a quantum gas in an artificial quasicrystal realized by a bichromatic optical lattice [1]. In this work we study a different frequency regime where excitation into higher bands is not significant, and the modulation frequency is high enough to avoid intraband excitations [2]. In this regime, the phase modulation allows us to control the sign and magnitude of the effective lattice depth of the phase-modulated secondary lattice [1]. By monitoring expansion of a Bose-Einstein Condensate in the modulated bichromatic lattice, we observed that the effective variation of the secondary lattice depth causes a number of localization-delocalization transitions as the phason drive amplitude is increased. These results open a new path to dynamical coherent control of the transport properties of quantum matter. |
Monday, March 6, 2023 8:48AM - 9:00AM |
A66.00003: Metals, Insulators, and Beyond in Quasi-Periodic Systems with Power-Law Hoppings Dan S Borgnia, Nicolò Defenu Recent analytic methods are applied to single-frequency quasi-periodic systems with power-law hoppings to generate an exact phase diagram. Taking advantage of Avila's Global Theory, we show the existence of a metallic phase and produce sharp bounds in the phase diagram. We then introduce self-dual power-law hopping models as a perturbation to the single-frequency operators to show the existence of an insulating phase both in the self-dual models and the single-frequency operators. This insulating phase survives via an exact perturbative expansion to the metallic transition at the cost of countably many gaps closings in the spectrum, generating a hierarchy of mixed spectra, consistent with existing numerical works. |
Monday, March 6, 2023 9:00AM - 9:12AM |
A66.00004: Disorder-Free Localization in a Two-Dimensional Lattice Gauge theory- Transition and Spectral Response Nilotpal Chakraborty, Markus Heyl, Petr Karpov, Roderich Moessner There has been great recent interest in realizing lattice gauge theories in the lab in various quantum simulator platforms. We show that there exists a disorder-free localization transition in two dimensions in a model of a lattice gauge theory with discrete degrees of freedom , namely the U(1) quantum link model, one of the target models for such quantum simulator experiments and also relevant for frustrated magents. We study the nature of localization transition using a percolation model and we show that in a certain regime of the Hamiltonian, the disorder-free localization transition is a continuous transition whose universality class we determine by calculating exact critical exponents [1]. We also calculate spectral features of such a localized system deep in the localized phase using a cluster expansion approach [2]. We show that such a localized system has sharp peaks in spatially averaged high temperature spectral functions combined with a vanishing response in the zero frequency limit, even in the infinite size limit. Our results highlight unique features of such disorder-free localization in lattice gauge theories which distinguish it from conventional many body localization in disordered systems as well as otherwise expected high temperature paramagnetic response in frustrated magnets. |
Monday, March 6, 2023 9:12AM - 9:24AM |
A66.00005: Short-time particle motion in a one-dimensional lattice with site disorder Bingyu Cui, Maxim Sukharev, Abraham Nitzan Like a free particle, the initial growth of a broad (relative to lattice spacing) wavepacket placed on an ordered lattice is slow (zero initial slope) and becomes linear in t at long time. On a disordered 1-dimensional lattice, the growth is inhibited at long time (Anderson localization). We consider site disorder with nearest-neighbor hopping on 1-dimensional systems, and show via numerical simulations supported by the analytical study that the short time growth of the particle distribution is faster on the disordered lattice than on the ordered one. Such faster spread takes place on time and length scale that may be relevant to the exciton motion in disordered systems. |
Monday, March 6, 2023 9:24AM - 9:36AM |
A66.00006: Emergence of quasiperiodic behaviour in transport and hybridisation properties of clean lattice systems Cecilie Glittum, Antonio Strkalj, Claudio Castelnovo Quasiperiodic behaviour is mostly known to occur in systems with enforced quasiperiodicity, in either the lattice structure or the potential, as well as in periodically driven systems. Here, we present instead a rarer setting where quasiperiodic behaviour emerges in clean, non-driven lattice systems. We illustrate this through two examples of experimental relevance, namely an infinite tight-binding chain with a gated segment, and a hopping particle coupled to static Ising degrees of freedom. We show how the quasiperiodic behaviour manifests in the number of states that are localised by the geometry of the system, with corresponding effects on transport and hybridisation properties. |
Monday, March 6, 2023 9:36AM - 9:48AM |
A66.00007: Applications of the Hubbard wheel: Quantum non-demolition readout and the role of disorder in an ensemble of qubits Reja H Wilke, Thomas Köhler, Felix A Palm, Sebastian Paeckel Easily realizable and scalable setups involving a center site with extensively scaling coordination number are important in quantum information. Recent work on a system of hardcore bosons on a wheel geometry, known to form a Bose-Einstein condensate, introduced a mechanism stabilizing a one-dimensional quantum many-body phase in the presence of nearest-neighbor interactions via the protection of an emergent Z2 symmetry. In this talk, I'll discuss the effect of further perturbations, relevant in more realistic setups in quantum simulation and central spin systems. Furthermore, I'll introduce a probe site for quantum non-demolition readout of many-particle states, allowing to predict the state of the BEC on the wheel. These novel theoretical insights will facilitate experimental realizations and interesting applications in various quantum platforms. |
Monday, March 6, 2023 9:48AM - 10:00AM |
A66.00008: Anomalous localization in a kicked quasicrystal Toshihiko Shimasaki, Max Prichard, Hasan Kondakci, Jared E Pagett, Peter Dotti, Alec Cao, Tsung-Cheng Lu, Tarun Grover, David M Weld We report experimental results on the anomalous transport and localization of the kicked Aubry-André-Harper (kAAH) model in an extended parameter space [1]. The experiment consists of loading a Bose-Einstein condensate in a static optical lattice then periodically applying a secondary lattice with a lattice constant incommensurate to the first lattice. The extended parameter space is reached by spectrally tailoring the pulses, which allows us to reduce interband excitation by minimizing unwanted spectral components. This “apodization” technique is a versatile new tool to experimentally implement a single-band lattice model in the presence of periodic driving. In our experiment this technique extends the range of accessible parameter space by 5 orders of magnitude and allows us to explore regions where anomalous transport has been predicted. We experimentally map out the phase diagram via transport measurements, and indeed observe anomalous transport in a wide range of parameter space in the phase diagram. We theoretically show that the observed anomalous transport is a result of the mixed spectra and, in particular, a nonvanishing fraction of critical eigenstates. We also discuss the connection to multifractality, which is theoretically predicted for the kAAH model. |
Monday, March 6, 2023 10:00AM - 10:12AM |
A66.00009: Multiple reentrant localisation transitions in quasiperiodic chains Antonio Strkalj, Hugo Tabanelli, Claudio Castelnovo Transport properties of quantum systems crucially depend on how ordered they are. Periodic order favours extended Bloch waves that generate metallic bands, whereas disorder is known to localise the motion of particles, especially in lower dimensions. In this context, quasiperiodic systems, which are neither periodic nor disordered, reveal exotic transport properties, self-similar wavefunctions, and critical phenomena. Here we present a theoretical study of localisation in quasiperiodic chains with modulated hoppings, which interpolate between two well-known quasiperiodic examples: the Aubry-André model, known for extended to critical phase transition, and the Fibonacci model, which is always critical. We find that the interpolating model has a non-monotonous and non-uniform behaviour of the spectrum. More precisely, we discover that by controllably evolving an Aubry-André into a Fibonacci model, multiple localisation-delocalisation transitions take place before the spectrum becomes critical. Our findings offer a unique new insight into understanding the criticality of quasiperiodic chains as well as a controllable knob by which to engineer band-selective pass filters. Furthermore, our model serves as a rich playground for studying the interplay between many-body interactions and tunable potentials. |
Monday, March 6, 2023 10:12AM - 10:24AM |
A66.00010: Spectrum-wide quantum criticality at the Anderson-Mott transition Xinghai Zhang, Matthew S Foster The interplay of interactions and Anderson localization has been studied intensively in recent years. In this work, we study the Anderson transition in interacting power-law random hopping models. These models interpolate between the random matrix and strong 1D localization limit, and the non-interacting version exhibits a “spectrum-wide quantum critical” (SWQC) metal-insulator transition (MIT), tuned by the hopping decay power. SWQC can play a role in both topological and strongly correlated superconductors [1]. Our previous numerical study demonstrated that the SWQC transition survives the incorporation of attractive Hubbard interactions, and strongly enhances Cooper pairing near the MIT [2]. Here we combine analytical and numerical approaches to determine how interactions shift the MIT, preserve or destroy SWQC, and mediate inelastic relaxation processes responsible for dephasing. |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700