Phonon and optical-roton branches of excitations of the Bose system

• URL: http://arxiv.org/abs/2205.14391v1
• Date: Sat, 28 May 2022 10:20:56 GMT
• Title: Phonon and optical-roton branches of excitations of the Bose system
• Authors: Yu.M. Poluektov and A.A. Soroka
• Abstract summary: The spectrum of elementary excitations of a many-particle Bose system is calculated. The dispersion of the phonon part of the spectrum is considered. The performed calculations and analysis of experiments on neutron scattering allow to make a statement about the complex structure of the Landau dispersion curve in the superfluid He-4.
• Score: 0.0
• License: http://creativecommons.org/licenses/by/4.0/
• Abstract: For a system of a large number of Bose particles, a chain of coupled equations for the averages of field operators is obtained. In the approximation where only the averages of one field operator and the averages of products of two operators at zero temperature are taken into account, there is derived a closed system of dynamic equations. Taking into account the finite range of the interaction potential between particles, the spectrum of elementary excitations of a many-particle Bose system is calculated, and it is shown that it has two branches: a sound branch and an optical branch with an energy gap at zero momentum. At high density, both branches are nonmonotonic and have the roton-like minima. The dispersion of the phonon part of the spectrum is considered. The performed calculations and analysis of experiments on neutron scattering allow to make a statement about the complex structure of the Landau dispersion curve in the superfluid He-4.

Related papers

• A Mass-in-Mass Chain and the Generalization of the Dirac Equation with an Eight-Component Wave Function and with Optical and Acoustic Branches of the Dispersion Relation [0.0]
  The paper considers a slightly modified one-dimensional infinite mass-in-mass chain. In the one-dimensional case, eight linearly independent solutions corresponding to eight combinations of two branches of dispersion, two signs of total energy, and two possible directions of spin orientation, each in the form of four plane waves, are obtained.
  arXiv  Detail & Related papers  (2024-01-22T15:56:54Z)
• Formation of robust bound states of interacting microwave photons [148.37607455646454]
  One of the hallmarks of interacting systems is the formation of multi-particle bound states. We develop a high fidelity parameterizable fSim gate that implements the periodic quantum circuit of the spin-1/2 XXZ model. By placing microwave photons in adjacent qubit sites, we study the propagation of these excitations and observe their bound nature for up to 5 photons.
  arXiv  Detail & Related papers  (2022-06-10T17:52:29Z)
• Classical analog of qubit logic based on a magnon Bose-Einstein condensate [52.77024349608834]
  We present a classical version of several quantum bit (qubit) functionalities using a two-component magnon Bose-Einstein condensate. The macroscopic wavefunctions of these two condensates serve as orthonormal basis states that form a system being a classical counterpart of a single qubit.
  arXiv  Detail & Related papers  (2021-11-12T16:14:46Z)
• Unconventional pairing in few-fermion systems tuned by external confinement [0.0]
  We study the ground-state properties of a two-component system of a few ultra-cold fermions with attractive interactions. We show that, by ramping up an external potential barrier felt by one of the components, it is possible to induce regions of exotic superfluid phases.
  arXiv  Detail & Related papers  (2021-05-26T12:39:26Z)
• Observation-dependent suppression and enhancement of two-photon coincidences by tailored losses [68.8204255655161]
  Hong-Ou-Mandel (HOM) effect can lead to a perfect suppression of two-particle coincidences between the output ports of a balanced beam splitter. In this work, we demonstrate experimentally that the two-particle coincidence statistics of two bosons can instead be seamlessly tuned to substantial enhancement. Our findings reveal a new approach to harnessing non-Hermitian settings for the manipulation of multi-particle quantum states.
  arXiv  Detail & Related papers  (2021-05-12T06:47:35Z)
• Bloch-Landau-Zener dynamics induced by a synthetic field in a photonic quantum walk [52.77024349608834]
  We realize a photonic quantum walk in the presence of a synthetic gauge field. We investigate intriguing system dynamics characterized by the interplay between Bloch oscillations and Landau-Zener transitions.
  arXiv  Detail & Related papers  (2020-11-11T16:35:41Z)
• Absorption and analysis of unbound quantum particles -- one by one [0.0]
  We present methods for calculating differential probabilities for unbound particles. In addition to attenuating outgoing waves, this absorber is also used to probe them by projection onto single-particle scattering states. We show how energy distributions of unbound particles may be determined on numerical domains considerably smaller than the actual extension of the system.
  arXiv  Detail & Related papers  (2020-10-06T12:48:03Z)
• Intercomponent entanglement entropy and spectrum in binary Bose-Einstein condensates [4.511923587827301]
  We study the entanglement entropy and spectrum between components in binary Bose-Einstein condensates in $d$ spatial dimensions. We employ effective field theory to show that the entanglement spectrum exhibits an anomalous square-root dispersion relation in the presence of an intercomponent tunneling (a Rabi coupling) and a gapped dispersion relation in its absence.
  arXiv  Detail & Related papers  (2020-09-07T08:58:00Z)
• Models of zero-range interaction for the bosonic trimer at unitarity [91.3755431537592]
  We present the construction of quantum Hamiltonians for a three-body system consisting of identical bosons mutually coupled by a two-body interaction of zero range. For a large part of the presentation, infinite scattering length will be considered.
  arXiv  Detail & Related papers  (2020-06-03T17:54:43Z)
• Localization of Rung Pairs in Hard-core Bose-Hubbard Ladder [13.46516066673]
  We study the rung-pair localization of the Bose-Hubbard ladder model without quenched disorder. In the hard-core limit, there exists a rung-pair localization both at the edges and in the bulk. Our results reveal another interesting type of disorder-free localization related to a zero-energy flat band.
  arXiv  Detail & Related papers  (2020-05-18T08:40:40Z)
• Dynamical solitons and boson fractionalization in cold-atom topological insulators [110.83289076967895]
  We study the $mathbbZ$ Bose-Hubbard model at incommensurate densities. We show how defects in the $mathbbZ$ field can appear in the ground state, connecting different sectors. Using a pumping argument, we show that it survives also for finite interactions.
  arXiv  Detail & Related papers  (2020-03-24T17:31:34Z)

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.