A5069430702- Quantum many-body systems
- Cold Atom Physics and Bose-Einstein Condensates
- Quantum and electron transport phenomena
- Physics of Superconductivity and Magnetism
- Quantum Information and Cryptography
- Quantum, superfluid, helium dynamics
- Advanced Thermodynamics and Statistical Mechanics
- Opinion Dynamics and Social Influence
- Quantum Computing Algorithms and Architecture
- Quantum chaos and dynamical systems
- Model Reduction and Neural Networks
- Quantum Mechanics and Applications
- Advanced Chemical Physics Studies
- Quantum optics and atomic interactions
- Magnetic properties of thin films
- Neural Networks and Reservoir Computing
- Tensor decomposition and applications
- Geochemistry and Geologic Mapping
- Mechanical and Optical Resonators
- Topological Materials and Phenomena
University of Geneva
2022-2024
Institute of Science and Technology Austria
2018-2022
University of Leeds
2018
University of Nottingham
2016
Recent realization of a kinetically-constrained chain Rydberg atoms by Bernien et al. [Nature 551, 579 (2017)] resulted in the observation unusual revivals many-body quantum dynamics. In our previous work [arXiv:1711.03528] such dynamics was attributed to existence "quantum scarred" eigenstates spectrum experimentally realized model. Here we present detailed study eigenstate properties same We find that majority exhibit anomalous thermalization: observable expectation values converge their...
The control of nonequilibrium quantum dynamics in many-body systems is challenging because interactions typically lead to thermalization and a chaotic spreading throughout Hilbert space. We investigate after rapid quenches system composed 3 200 strongly interacting qubits one two spatial dimensions. Using programmable simulator based on Rydberg atom arrays, we show that coherent revivals associated with so-called scars can be stabilized by periodic driving, which generates robust subharmonic...
Motivated by recent experimental observations of coherent many-body revivals in a constrained Rydberg atom chain, we construct weak quasi-local deformation the blockade Hamiltonian, which makes virtually perfect. Our analysis suggests existence an underlying non-integrable Hamiltonian supports emergent SU(2)-spin dynamics within small subspace Hilbert space. We show that such perfect necessitates atypical, nonergodic energy eigenstates - quantum scars. Furthermore, using these insights, toy...
Variational quantum algorithms are promising for achieving advantage on near-term devices. The hardware is used to implement a variational wave function and measure observables, whereas the classical computer store update parameters. optimization landscape of expressive ans\"atze however dominated by large regions in parameter space, known as barren plateaus, with vanishing gradients which prevents efficient optimization. In this work we propose general algorithm avoid plateaus...
Engineered dissipative reservoirs have the potential to steer many-body quantum systems toward correlated steady states useful for simulation of high-temperature superconductivity or magnetism. Using up 49 superconducting qubits, we prepared low-energy transverse-field Ising model through coupling auxiliary qubits. In one dimension, observed long-range correlations and a ground-state fidelity 0.86 18 qubits at critical point. two dimensions, found mutual information that extends beyond...
The entanglement spectrum of the reduced density matrix contains information beyond von Neumann entropy and provides unique insights into exotic orders or critical behavior quantum systems. Here, we show that strongly disordered systems in many-body localized phase have power-law spectra, arising from presence extensively many local integrals motion. distinguishes ergodic systems, as well ground states gapped integrable models free vicinity scale-invariant points. We confirm our results...
Relaxation of few-body quantum systems can strongly depend on the initial state when system's semiclassical phase space is mixed, i.e., regions chaotic motion coexist with regular islands. In recent years, there has been much effort to understand process thermalization in interacting that often lack an obvious limit. Time-dependent variational principle (TDVP) allows systematically derive effective classical (nonlinear) dynamical system by projecting unitary many-body dynamics onto a...
This paper proposes different mechanisms to realize robust quantum scars in two-dimensional arrays of Rydberg atoms. The results show that a small perturbation the system can lead significant suppression thermalization rate set states
The analogy between an equilibrium partition function and the return probability in many-body unitary dynamics has led to concept of dynamical quantum phase transition (DQPT). DQPTs are defined by nonanalyticities amplitude present many models. In some cases, can be related concepts, such as order parameters, yet their universal description is open question. this Letter, we provide first steps toward a classification using matrix product state thermodynamic limit. This allows us distinguish...
Systems of correlated particles appear in many fields modern science and represent some the most intractable computational problems nature. The challenge these systems arises when interactions become comparable to other energy scales, which makes state each particle depend on all particles1. lack general solutions for three-body problem acceptable theory strongly electrons shows that our understanding fades number or interaction strength increases. One hallmarks interacting is formation...
The control of many-body quantum dynamics in complex systems is a key challenge the quest to reliably produce and manipulate large-scale entangled states. Recently, quench experiments Rydberg atom arrays [Bluvstein et al. Science 371, 1355 (2021)] demonstrated that coherent revivals associated with scars can be stabilized by periodic driving, generating stable subharmonic responses over wide parameter regime. We analyze simple, related model where these phenomena originate from...
Chains of superconducting devices provide a natural platform for exploration synthetic bosonic quantum matter, and the possibility to tune parametric disorder $i\phantom{\rule{0}{0ex}}n$ $s\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}u$ makes them an ideal framework study localization physics in particular. Here, authors demonstrate that by tuning strength via external magnetic field, one can probe both ergodic many-body localized phases disordered Hubbard model....
Probing correlated states of many-body systems is one the central tasks for quantum simulators and processors. A promising approach to state preparation realize desired as steady engineered dissipative evolution. recent experiment with a Google superconducting processor [X. Mi , Science 383, 1332 (2024)] demonstrated cooling algorithm utilizing auxiliary degrees freedom that are periodically reset remove quasiparticles from system, thereby driving it towards its ground state. In this work,...
Many-body quantum systems typically display fast dynamics and ballistic spreading of information. Here we address the open problem how slow can be after a generic breaking integrability by local interactions. We develop method based on degenerate perturbation theory that reveals dynamical regimes delocalization processes in general translation invariant models, along with accurate estimates their time scales. Our results shed light fundamental questions robustness integrable possibility...
Eigenstate thermalization in quantum many-body systems implies that eigenstates at high energy are similar to random vectors. Identifying where least some nonthermal is an outstanding question. In this Letter we show interacting models have a nullspace---a degenerate subspace of zero (zero modes), which corresponds infinite temperature, provide route eigenstates. We analytically the existence mode can be represented as matrix product state for certain class local Hamiltonians. more general...
Nonanalytic points in the return probability of a quantum state as function time, known dynamical phase transitions (DQPTs), have received great attention recent years, but understanding their mechanism is still incomplete. In our work [Phys. Rev. Lett. 126, 040602 (2021)], we demonstrated that one-dimensional DQPTs can be produced by two distinct mechanisms, namely semiclassical precession and entanglement generation, leading to definition (pDQPTs) (eDQPTs) transitions. this manuscript,...
Engineered dissipative reservoirs have the potential to steer many-body quantum systems toward correlated steady states useful for simulation of high-temperature superconductivity or magnetism. Using up 49 superconducting qubits, we prepared low-energy transverse-field Ising model through coupling auxiliary qubits. In one dimension, observed long-range correlations and a ground-state fidelity 0.86 18 qubits at critical point. two dimensions, found mutual information that extends beyond...
The approach to equilibrium in interacting classical and quantum systems is a challenging problem of both theoretical experimental interest. One useful organizing principle characterizing equilibration the dissipative universality class, most prevalent one being diffusion. In this paper, we use effective field theory (EFT) diffusion systematically obtain universal power-law corrections We then employ large-scale simulations explore their validity. particular, find scaling functions for...
Many-body localization (MBL) is an example of a dynamical phase matter that avoids thermalization. While the MBL robust to weak local perturbations, fate system coupled thermalizing quantum represents "heat bath" open question actively investigated theoretically and experimentally. In this work we consider stability Anderson insulator with finite density particles interacting single mobile impurity -- small bath. We give perturbative arguments support in strong interaction regime. Large...
Thermalizing and localized many-body quantum systems present two distinct dynamical phases of matter. Recently the fate a system coupled to thermalizing viewed as bath received significant theoretical experimental attention. In this work, we study mobile impurity, representing small bath, that interacts locally with an Anderson insulator finite density particles. Using static Hartree approximation obtain effective disorder strength, formulate analytic criterion for perturbative stability...
Probing correlated states of many-body systems is one the central tasks for quantum simulators and processors. A promising approach to state preparation realize desired as steady engineered dissipative evolution. recent experiment with a Google superconducting processor [X. Mi et al., Science 383, 1332 (2024)] demonstrated cooling algorithm utilizing auxiliary degrees freedom that are periodically reset remove quasiparticles from system, thereby driving it towards ground state. We develop...
Transport and the approach to equilibrium in interacting classical quantum systems is a challenging problem of both theoretical experimental interest. One useful organizing principle characterizing equilibration dissipative universality class, most prevalent one being diffusion. In this paper, we use effective field theory (EFT) diffusion systematically obtain universal power-law corrections We then employ large-scale simulations explore their validity. particular, find scaling functions for...