Bound states in semi-Dirac semi-metals
- URL: http://arxiv.org/abs/2007.01643v1
- Date: Fri, 3 Jul 2020 12:22:19 GMT
- Title: Bound states in semi-Dirac semi-metals
- Authors: David Krejcirik and Pedro. R. S. Antunes
- Abstract summary: The transport properties of nanostructures with a linear dispersion along one direction and a quadratic dispersion along another are studied.
One of the most interesting features of the analysis is the evident spectral instability of the systems in the weakly coupled regime.
- Score: 0.0
- License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
- Abstract: New insights into transport properties of nanostructures with a linear
dispersion along one direction and a quadratic dispersion along another are
obtained by analysing their spectral stability properties under small
perturbations. Physically relevant sufficient and necessary conditions to
guarantee the existence of discrete eigenvalues are derived under rather
general assumptions on external fields. One of the most interesting features of
the analysis is the evident spectral instability of the systems in the weakly
coupled regime. The rigorous theoretical results are illustrated by numerical
experiments and predictions for physical experiments are made.
Related papers
- Bistability and Exact Reflectionless States in Nonlinear Scattering of a Bose--Einstein Condensate [9.521680081185691]
We investigate the mean-field scattering dynamics of a quasi-one-dimensional Bose--Einstein condensate interacting with a Rosen--Morse potential.<n>For specific potential and nonlinearity parameters, we derive analytically exact, degenerate scattering states exhibiting perfect transmission.<n>Our work establishes an analytic framework for these multistable transmission phenomena.
arXiv Detail & Related papers (2025-11-05T06:47:08Z) - Discrete State Diffusion Models: A Sample Complexity Perspective [43.61958734990224]
We present a principled theoretical framework for discrete-state diffusion, providing the first sample complexity bound of $widetildemathcalO(epsilon-2)$.<n>Our structured decomposition of the score estimation error into statistical, approximation, optimization, and clipping components offers critical insights into how discrete-state models can be trained efficiently.
arXiv Detail & Related papers (2025-10-12T23:33:46Z) - Grassmann Variational Monte Carlo with neural wave functions [45.935798913942904]
We formalize the framework introduced by Pfau et al.citepfau2024accurate in terms of Grassmann geometry of the Hilbert space.<n>We validate our approach on the Heisenberg quantum spin model on the square lattice, achieving highly accurate energies and physical observables for a large number of excited states.
arXiv Detail & Related papers (2025-07-14T13:53:13Z) - Stability Analysis of Physics-Informed Neural Networks via Variational Coercivity, Perturbation Bounds, and Concentration Estimates [0.0]
PINNs approximate solutions to partial differential equations (PDEs) by minimizing residual-based losses over sampled collocation points.<n>We derive deterministic stability bounds that quantify how bounded perturbations in the network output propagate through both residual and supervised loss components.<n>This work provides a mathematically grounded and practically applicable stability framework for PINNs, clarifying the role of operator structure, sampling design, and functional regularity in robust training.
arXiv Detail & Related papers (2025-06-16T14:41:15Z) - Experimental Observation of Single- and Multi-Site Matter-Wave Solitons in 1D Optical Lattices [0.0]
We report the experimental observation of discrete bright matter-wave solitons with attractive interaction in an optical lattice.<n>Results reveal the existence and characteristics of these solitons across a range of lattice depths and spacings.
arXiv Detail & Related papers (2025-04-15T10:17:12Z) - Symmetries, Conservation Laws and Entanglement in Non-Hermitian Fermionic Lattices [37.69303106863453]
Non-Hermitian quantum many-body systems feature steady-state entanglement transitions driven by unitary dynamics and dissipation.<n>We show that the steady state is obtained by filling single-particle right eigenstates with the largest imaginary part of the eigenvalue.<n>We illustrate these principles in the Hatano-Nelson model with periodic boundary conditions and the non-Hermitian Su-Schrieffer-Heeger model.
arXiv Detail & Related papers (2025-04-11T14:06:05Z) - Experimentally Probing Non-Hermitian Spectral Transition and Eigenstate Skewness [19.452215199792924]
Non-Hermitian (NH) systems exhibit intricate spectral topology arising from complex-valued eigenenergies.
We present a Green's function-based method that enables the direct measurement and characterization of both complex-valued energy spectra and the left and right eigenstates.
arXiv Detail & Related papers (2025-01-14T14:40:05Z) - Quantum-electrodynamical density-functional theory for the Dicke Hamiltonian [0.0]
A detailed analysis of density-functional theory for quantum-electrodynamical model systems is provided.
In particular, the quantum Rabi model, the Dicke model, and the latter to multiple modes are considered.
arXiv Detail & Related papers (2024-09-18T12:53:36Z) - A Quantum Information Perspective on Many-Body Dispersive Forces [0.0]
We show how entanglement monogamy determines whether many-body corrections to the pair potential are attractive, repulsive, or zero.
These findings, demonstrated in trimers and extended lattices, apply in more general chemical environments where dispersion coexists with other cohesive forces.
arXiv Detail & Related papers (2024-07-04T18:30:40Z) - Nodal Spectral Functions Stabilized by Non-Hermitian Topology of Quasiparticles [0.0]
We discuss how the abundance and stability of nodal phases is drastically affected by NH topology.
We study a microscopic lattice model in which a sublattice-dependent interaction stabilizes nodal spectral functions.
arXiv Detail & Related papers (2024-05-08T18:00:06Z) - Envelope-function theory of inhomogeneous strain in semiconductor nanostructures [0.0]
Strain is an ubiquitous feature in semiconductor heterostructures, and can be engineered by different means to improve the properties of devices.
Here, we generalize the theory of Bir and Pikus to the case of inhomogeneous strain.
By fully accounting for the relativistic effects and metric aspects of the problem, we derive a complete envelope-function Hamiltonian.
arXiv Detail & Related papers (2023-12-26T09:27:39Z) - Hoeffding decomposition of black-box models with dependent inputs [30.076357972854723]
We generalize Hoeffding's decomposition for dependent inputs under mild conditions.
We show that any square-integrable, real-valued function of random elements respecting two assumptions can be uniquely additively and offer a characterization.
arXiv Detail & Related papers (2023-10-10T12:28:53Z) - Identifiability and Asymptotics in Learning Homogeneous Linear ODE Systems from Discrete Observations [114.17826109037048]
Ordinary Differential Equations (ODEs) have recently gained a lot of attention in machine learning.
theoretical aspects, e.g., identifiability and properties of statistical estimation are still obscure.
This paper derives a sufficient condition for the identifiability of homogeneous linear ODE systems from a sequence of equally-spaced error-free observations sampled from a single trajectory.
arXiv Detail & Related papers (2022-10-12T06:46:38Z) - Semirelativistic Potential Modelling of Bound States: Advocating Due
Rigour [0.0]
The Poincar'e-covariant quantum-field-theoretic description of bound states by the homogeneous Bethe-Salpeter equation exhibits an intrinsic complexity.
The resulting approximate outcome's reliability can be assessed by applying several rigorous constraints on the nature of the bound-state spectra.
arXiv Detail & Related papers (2022-08-17T07:02:01Z) - Exceptional dynamics of interacting spin liquids [3.127528121347748]
We show that interactions in quantum spin liquids can result in non-Hermitian phenomenology.
We show the generic appearance of exceptional points and rings depending on the symmetry of the system.
arXiv Detail & Related papers (2022-02-07T19:00:02Z) - A Theoretical Analysis on Independence-driven Importance Weighting for
Covariate-shift Generalization [44.88645911638269]
independence-driven importance algorithms in stable learning literature have shown empirical effectiveness.
In this paper, we theoretically prove the effectiveness of such algorithms by explaining them as feature selection processes.
We prove that under ideal conditions, independence-driven importance weighting algorithms could identify the variables in this set.
arXiv Detail & Related papers (2021-11-03T17:18:49Z) - Quantum correlations, entanglement spectrum and coherence of
two-particle reduced density matrix in the Extended Hubbard Model [62.997667081978825]
We study the ground state properties of the one-dimensional extended Hubbard model at half-filling.
In particular, in the superconducting region, we obtain that the entanglement spectrum signals a transition between a dominant singlet (SS) to triplet (TS) pairing ordering in the system.
arXiv Detail & Related papers (2021-10-29T21:02:24Z) - Spectral density reconstruction with Chebyshev polynomials [77.34726150561087]
We show how to perform controllable reconstructions of a finite energy resolution with rigorous error estimates.
This paves the way for future applications in nuclear and condensed matter physics.
arXiv Detail & Related papers (2021-10-05T15:16:13Z) - Visualizing spinon Fermi surfaces with time-dependent spectroscopy [62.997667081978825]
We propose applying time-dependent photo-emission spectroscopy, an established tool in solid state systems, in cold atom quantum simulators.
We show in exact diagonalization simulations of the one-dimensional $t-J$ model that the spinons start to populate previously unoccupied states in an effective band structure.
The dependence of the spectral function on the time after the pump pulse reveals collective interactions among spinons.
arXiv Detail & Related papers (2021-05-27T18:00:02Z) - Quantum particle across Grushin singularity [77.34726150561087]
We study the phenomenon of transmission across the singularity that separates the two half-cylinders.
All the local realisations of the free (Laplace-Beltrami) quantum Hamiltonian are examined as non-equivalent protocols of transmission/reflection.
This allows to comprehend the distinguished status of the so-called bridging' transmission protocol previously identified in the literature.
arXiv Detail & Related papers (2020-11-27T12:53:23Z)
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.