We have prepared two ultracold fermionic atoms in an isolated double-well potential and obtained full control over the quantum state of this system. In particular, we can independently control the interaction strength between the particles, their tunneling rate between the wells and the tilt of the potential. By introducing repulsive (attractive) interparticle interactions we have realized the two-particle analog of a Mott-insulating (charge-density-wave) state. We have also spectroscopically observed how second-order tunneling affects the energy of the system. This work realizes the first step of a bottom-up approach to deterministically create a single-site addressable realization of a ground-state Fermi-Hubbard system.
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http://dx.doi.org/10.1103/PhysRevLett.114.080402 | DOI Listing |
Phys Rev Lett
November 2024
Dipartimento di Fisica, Università di Genova, Via Dodecaneso 33, 16146 Genova, Italy.
We investigate the performance of a one-dimensional dimerized XY chain as a spin quantum battery. Such integrable model shows a rich quantum phase diagram that emerges through a mapping of the spins onto auxiliary fermionic degrees of freedom. We consider a charging protocol relying on the double quench of an internal parameter, namely the strength of the dimerization, and address the energy stored in the systems.
View Article and Find Full Text PDFNat Commun
November 2024
Department of Physics, The City College of New York-CUNY, New York, NY, 10031, USA.
Chirality - a characteristic handedness that distinguishes 'left' from 'right'-is a fundamental property of quantum particles under broken symmetry intimately connected to their spins. Chiral fermions have been identified in Weyl semimetals through their unique electrodynamics arising from 'axial' charge imbalance between pairs of chiral Weyl nodes-the topologically protected 'relativistic' crossings of electronic bands. Chiral magnetotransport phenomena critically depend on the details of electronic band structure.
View Article and Find Full Text PDFJ Chem Phys
October 2024
H. H. Wills Physics Laboratory, University of Bristol, Bristol BS8 1TL, United Kingdom.
The most general description of quantum evolution up to a time τ is a completely positive tracing preserving map known as a dynamical mapΛ̂(τ). Here, we consider Λ̂(τ) arising from suddenly coupling a system to one or more thermal baths with a strength that is neither weak nor strong. Given no clear separation of characteristic system/bath time scales, Λ̂(τ) is generically expected to be non-Markovian; however, we do assume the ensuing dynamics has a unique steady state, implying the baths possess a finite memory time τm.
View Article and Find Full Text PDFPhys Rev Lett
September 2024
Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Strasse 38, 01187 Dresden, Germany.
The Luttinger model is a paradigm for the breakdown due to interactions of the Fermi liquid description of one-dimensional massless Dirac fermions. Attempts to discretize the model on a one-dimensional lattice have failed to reproduce the established bosonization results because of the fermion-doubling obstruction: a local and symmetry-preserving discretization of the Hamiltonian introduces a spurious second species of low-energy excitations, while a nonlocal discretization opens a single-particle gap at the Dirac point. Here, we show how to work around this obstruction by discretizing both space and time to obtain a local Lagrangian for a helical Luttinger liquid with Hubbard interaction.
View Article and Find Full Text PDFNat Commun
September 2024
Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba, 277-8581, Japan.
The mixed-valence compound YbB displays paradoxical quantum oscillations in electrical resistivity and magnetic torque in a regime with a well-developed insulating charge gap and in the absence of an electronic Fermi surface. However, signatures of such unusual fermionic quasiparticles in other bulk thermodynamic observables have been missing. Here we report the observation of a series of sharp double-peak features in the specific heat as a function of the magnetic field.
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