Two Channel Kondo behavior in the quantum XX chain with a boundary defect

• URL: http://arxiv.org/abs/2501.16415v1
• Date: Mon, 27 Jan 2025 19:00:00 GMT
• Title: Two Channel Kondo behavior in the quantum XX chain with a boundary defect
• Authors: Yicheng Tang, Pradip Kattel, J. H. Pixley, Natan Andrei,
• Abstract summary: We show that a boundary defect in the single spin-$frac12$ quantum $XX$ chain exhibits two-channel Kondo physics. The defect leads to non-trivial boundary behavior characteristic of the two-channel Kondo model.
• Score: 0.0
• License:
• Abstract: We demonstrate that a boundary defect in the single spin-$\frac{1}{2}$ quantum $XX$ chain exhibits two-channel Kondo physics. Due to the presence of the defect, the edge spin fractionalizes into two Majorana fermions, out of which one decouples, and one is overscreened by the free fermion in bulk, leading to non-trivial boundary behavior characteristic of the two-channel Kondo model. When the ratio of boundary to bulk coupling exceeds a critical value of $\sqrt{2}$, a massive boundary-bound mode is exponentially localized near the impurity site for strong impurity coupling. This leads to unusual behavior in physical quantities, such as the $g$-function not being monotonic. We compute the $g-$function of the impurity from both thermodynamic and entanglement entropy calculations and show that it takes a non-integer value of $\sqrt{2}$ just as in the two-channel Kondo problem.

Related papers

• Hamiltonians for Quantum Systems with Contact Interactions [49.1574468325115]
  We show that in the limit one obtains the one-body Hamiltonian for the light particle subject to $N$ (non-local) point interactions placed at fixed positions. We will verify that such non-local point interactions do not exhibit the ultraviolet pathologies that are present in the case of standard local point interactions.
  arXiv  Detail & Related papers  (2024-07-09T14:04:11Z)
• Casimir Energy in (2 + 1)-Dimensional Field Theories [44.99833362998488]
  Two types of boundary conditions give rise to two different exponential decay regimes of the Casimir energy at large distances. Non-perturbative numerical simulations and analytical arguments show such an exponential decay for Dirichlet boundary conditions of SU(2) gauge theories.
  arXiv  Detail & Related papers  (2024-05-06T18:08:31Z)
• Hamiltonian for a Bose gas with Contact Interactions [49.1574468325115]
  We study the Hamiltonian for a Bose gas in three dimensions of $N geq 3$ spinless particles interacting via zero-range or contact interactions.
  arXiv  Detail & Related papers  (2024-03-19T10:00:12Z)
• Tunable quantum criticality and pseudocriticality across the fixed-point annihilation in the anisotropic spin-boson model [0.26107298043931204]
  We study the nontrivial renormalization-group scenario of fixed-point annihilation in spin-boson models. We find a tunable transition between two localized phases that can be continuous or strongly first-order. We also find scaling behavior at the symmetry-enhanced first-order transition, for which the inverse correlation-length exponent is given by the bath exponent.
  arXiv  Detail & Related papers  (2024-03-04T19:00:07Z)
• Decoherence through Ancilla Anyon Reservoirs [0.0]
  We take the critical boundary of the $2d$ toric code as an example. The intrinsic nonlocal nature of the anyons demands the strong and weak symmetry condition for the ordinary decoherence problem. We show that decoherence-analogues of Majorana zero modes are localized at the spatial interface of the relevant $e$ and $m$ anyon decoherence channels.
  arXiv  Detail & Related papers  (2023-12-07T19:00:09Z)
• Kondo effect in the isotropic Heisenberg spin chain [0.0]
  impurity coupling strength is much weaker than that in the bulk, the impurity is screened in the ground state via the Kondo effect. When the impurity coupling is ferromagnetic, the impurity is unscreened in the ground state. When the absolute value of the ratio of the impurity and bulk coupling strengths is greater than $frac45$, the impurity can be screened by adding a bound mode.
  arXiv  Detail & Related papers  (2023-11-17T15:09:23Z)
• Detecting bulk and edge exceptional points in non-Hermitian systems through generalized Petermann factors [7.371841894852217]
  Non-orthogonality in non-Hermitian quantum systems gives rise to tremendous exotic quantum phenomena. We introduce an interesting quantity (denoted as $eta$) as a new variant of the Petermann factor to measure non-unitarity.
  arXiv  Detail & Related papers  (2022-08-31T16:24:03Z)
• Frustration shapes multi-channel Kondo physics: a star graph perspective [0.31317409221921144]
  We study the overscreened multi-channel Kondo (MCK) model using the recently developed unitary renormalization group (URG) technique. Our results display the importance of ground state degeneracy in explaining various important properties.
  arXiv  Detail & Related papers  (2022-05-02T10:21:24Z)
• Annihilating Entanglement Between Cones [77.34726150561087]
  We show that Lorentz cones are the only cones with a symmetric base for which a certain stronger version of the resilience property is satisfied. Our proof exploits the symmetries of the Lorentz cones and applies two constructions resembling protocols for entanglement distillation.
  arXiv  Detail & Related papers  (2021-10-22T15:02:39Z)
• Spectrum of localized states in fermionic chains with defect and adiabatic charge pumping [68.8204255655161]
  We study the localized states of a generic quadratic fermionic chain with finite-range couplings. We analyze the robustness of the connection between bands against perturbations of the Hamiltonian.
  arXiv  Detail & Related papers  (2021-07-20T18:44:06Z)
• Scattering data and bound states of a squeezed double-layer structure [77.34726150561087]
  A structure composed of two parallel homogeneous layers is studied in the limit as their widths $l_j$ and $l_j$, and the distance between them $r$ shrinks to zero simultaneously. The existence of non-trivial bound states is proven in the squeezing limit, including the particular example of the squeezed potential in the form of the derivative of Dirac's delta function. The scenario how a single bound state survives in the squeezed system from a finite number of bound states in the finite system is described in detail.
  arXiv  Detail & Related papers  (2020-11-23T14:40:27Z)

This list is automatically generated from the titles and abstracts of the papers in this site.

This site does not guarantee the quality of this site (including all information) and is not responsible for any consequences.