Title: Exact solution of the topological symplectic Kondo problem

Abstract

The Kondo effect is an archetypical phenomenon in the physics of strongly correlated electron systems. Recent attention has focused on the application of Kondo physics to quantum information science by exploiting overscreened Kondo impurities with residual anyon-like impurity entropy. While this physics was proposed in the fine-tuned multi-channel Kondo setup or in the Majorana-based topological Kondo effect, we here study the Kondo effect with symplectic symmetry Sp(2k) and present details about the implementation which importantly only involves conventional s-wave superconductivity coupled to an array of resonant levels and neither requires perfect channel symmetry nor Majorana fermions. Here we carefully discuss the role of perturbations and show that a global Zeeman drives the system to a 2-channel SU(k) fixed point. Exact results for the residual entropy, specific heat and magnetization are derived using the thermodynamic Bethe Ansatz for Sp(2k). This solution not only proves the existence of a quantum critical ground state with anyon-like Hilbert space dimension, but also a particularly weak non-Fermi liquid behavior at criticality. We interpret the weakness of non-analyticities as a manifestation of suppressed density of states at the impurity causing only a very weak connection of putative anyons and conduction electrons. Given this weak connection, themore » simplicity of the design and the stability of the effect, we conjecture that the symplectic Kondo effect may be particularly suitable for quantum information applications.« less

Authors:

König, Elio J.  ^[1];

• Search DOE PAGES for author "König, Elio J."
• Search DOE PAGES for ORCID "0000-0002-5009-8881"

Tsvelik, Alexei M.  ^[2]

• Search DOE PAGES for author "Tsvelik, Alexei M."
• Search DOE PAGES for ORCID "0000-0002-7478-670X"

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+ Show Author Affiliations

1. Max Planck Institute of Solid State Research, Stuttgart (Germany)
2. Brookhaven National Lab. (BNL), Upton, NY (United States)

Publication Date:

Thu Jan 26 00:00:00 EST 2023

Research Org.:

Brookhaven National Laboratory (BNL), Upton, NY (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES). Materials Sciences & Engineering Division (MSE); USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1972468

Alternate Identifier(s):

OSTI ID: 1996447

Report Number(s):

BNL-224273-2023-JAAM
Journal ID: ISSN 0003-4916; TRN: US2313804

Grant/Contract Number:  

SC0012704

Resource Type:

Accepted Manuscript

Journal Name:

Annals of Physics

Additional Journal Information:

Journal Volume: 456; Journal ID: ISSN 0003-4916

Publisher:

Elsevier

Country of Publication:

United States

Language:

English

Subject:

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; Kondo effect; Bethe Ansatz; Anyons; Quantum criticality; Quantum dots