Non-Hermitian Squeezed Polarons

Abstract

Recent experimental breakthroughs in non-Hermitian ultracold atomic lattices have dangled tantalizing prospects in realizing exotic, hitherto unreported, many-body non-Hermitian quantum phenomena. In this work, we discover and propose an experimental platform for a radically different non-Hermitian phenomenon dubbed polaron squeezing. It is marked by a dipole-like accumulation of fermions arising from an interacting impurity in a background of non-Hermitian reciprocity-breaking hoppings. We computed their spatial density and found that, unlike Hermitian polarons which are symmetrically localized around impurities, non-Hermitian squeezed polarons localize asymmetrically in the direction opposite to conventional non-Hermitian pumping and non-perturbatively modify the entire spectrum, despite having a manifestly local profile. We investigated their time evolution and found that, saliently, they appear almost universally in the long-time steady state, unlike Hermitian polarons which only exist in the ground state. In our numerics, we also found that, unlike well-known topological or skin localized states, squeezed polarons exist in the bulk, independently of boundary conditions. Our findings could inspire the realization of many-body states in ultracold atomic setups, where a squeezed polaron can be readily detected and characterized by imaging the spatial fermionic density.

29 pages, 13 figures, update references, published version

References in corpus (36)

• The physics of exceptional points
• Spin-Injection Spectroscopy of a Spin-Orbit Coupled Fermi Gas
• Observation of Fermi Polarons in a Tunable Fermi Liquid of Ultracold Atoms
• A Bose-Einstein Condensate in a Uniform Light-induced Vector Potential
• Attractive and repulsive Fermi polarons in two dimensions
• QuSpin: a Python Package for Dynamics and Exact Diagonalisation of Quantum Many Body Systems part I: spin chains
• Observation of Non-Hermitian Skin Effect and Topology in Ultracold Atoms
• Repulsive Fermi polarons in a resonant mixture of ultracold ${}^6$Li atoms
• Normal state of a polarized Fermi gas at unitarity
• Tunable non-reciprocal quantum transport through a dissipative Aharonov-Bohm ring in ultracold atoms
• Gain and loss induced topological insulating phase in a non Hermitian electrical circuit
• Manipulating Topological Edge Spins in One-Dimensional Optical Lattice
• Many-body localization in a non-Hermitian quasi-periodic system
• Many-body topology of non-Hermitian systems
• Trimers, molecules and polarons in imbalanced atomic Fermi gases
• Polaron-molecule transitions in a two-dimensional Fermi gas
• Symmetry breaking and spectral structure of the interacting Hatano-Nelson model
• Highly polarized Fermi gases in two dimensions
• Quantum anomaly, non-Hermitian skin effects, and entanglement entropy in open systems
• Non-Hermitian Many-Body Localization with Open Boundaries
• Observation of coherent multiorbital polarons in a two-dimensional Fermi gas
• Polarons and Molecules in a Two-Dimensional Fermi Gas
• Experimental identification of the second-order non-Hermitian skin effect with physics-graph-informed machine learning
• Polarons in Ultracold Fermi Superfluids
• Decay of polarons and molecules in a strongly polarized Fermi gas
• Polaronic atom-trimer continuity in three-component Fermi gases
• Universal impurity-induced bound state in topological superfluids
• Designing non-Hermitian real spectra through electrostatics
• Molecule and polaron in a highly polarized two-dimensional Fermi gas with spin-orbit coupling
• Light-induced phase crossovers in a quantum spin Hall system
• Crossover polarons in a strongly interacting Fermi superfluid
• The p-wave polaron
• Dynamical formation of polarons in a Bose-Einstein condensate: A variational approach
• Finite-range effects in the unitary Fermi polaron
• Center-of-mass-momentum-dependent interaction between ultracold atoms
• Polaron in a $p+ip$ Fermi topological superfluid

Cited by in corpus (20)

• Topological Non-Hermitian skin effect
• Anomalous Skin Effects in Disordered Systems with a Single non-Hermitian Impurity
• Enhancement of Second-Order Non-Hermitian Skin Effect by Magnetic Fields
• Dimensional transmutation from non-Hermiticity
• Universal competitive spectral scaling from the critical non-Hermitian skin effect
• Designing non-Hermitian real spectra through electrostatics
• Non-Hermitian strongly interacting Dirac fermions: a quantum Monte-Carlo study
• Proposal for Observing Yang-Lee Criticality in Rydberg Atomic Arrays
• Non-Hermitian skin effect in one-dimensional interacting Bose gas
• High-fidelity realization of the AKLT state on a NISQ-era quantum processor
• Occupation-dependent particle separation in one-dimensional non-Hermitian lattices
• Mixed higher-order topology: boundary non-Hermitian skin effect induced by a Floquet bulk
• Fate of exceptional points under interactions: Reduction of topological classifications
• Kinked linear response from non-Hermitian cold-atom pumping
• Anomalous Andreev Spectrum and Transport in Non-Hermitian Josephson Junctions
• Non-Hermitian Skin Effect Along Hyperbolic Geodesics
• Nonlinear Hall effects with an exceptional ring
• Non-Hermitian ultra-strong bosonic clustering through interaction-induced caging
• Unified Multipole Bott Indices for Non-Hermitian Skin Effect in Different Orders
• Interacting many-body non-Hermitian systems as Markov chains