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We study the general quantum Hamiltonian that can be realized with two species of mutually interacting degenerate ultracold atoms in a ring-shaped trap, with the options of rotation and an azimuthal lattice. We examine the spectrum and the…

Quantum Gases · Physics 2023-11-28 Tomáš Opatrný , Kunal K. Das

One-particle properties of non-interacting Fermions in a one-dimensional harmonic trap and at zero temperature are studied. Exact expressions and asymptotic results for large Fermion number N are given for the particle density distribution…

Quantum Physics · Physics 2009-11-06 F. Gleisberg , W. Wonneberger , U. Schloeder , C. Zimmermann

We provide a detailed analysis of our previously proposed scheme [Phys. Rev. Lett. 88, 180401, (2002)] to engineer the profile of the hopping amplitudes for atomic gases in a 1D optical lattice so that the particle number becomes…

Other Condensed Matter · Physics 2008-11-26 J. Ruostekoski , J. Javanainen , G. V. Dunne

From the perspective of Sen entropy function, we study the geometric and algebraic properties of a class of (extremal) black holes in $ D \geq 4 $ spacetimes. For a given moduli space manifold, we describe the thermodynamic geometry away…

High Energy Physics - Theory · Physics 2011-09-05 Bhupendra Nath Tiwari

Atomic spectroscopy, an essential tool for frequency estimation, is widely used in quantum sensing. Atom-atom interaction can be used to generate entanglement for achieving quantum enhanced sensing. However, atom-atom interaction always…

Quantum Physics · Physics 2022-10-31 Jiahao Huang , Sijie Chen , Min Zhuang , Chaohong Lee

The possible compatibility of density matrices for single-party subsystems is described by linear constraints on their respective spectra. Whenever some of those quantum marginal constraints are saturated, the total quantum state has a…

Quantum Physics · Physics 2017-11-09 Christian Schilling , Carlos L. Benavides-Riveros , Péter Vrana

We derive the spectral density of the equiprobable mixture of two random density matrices of a two-level quantum system. We also work out the spectral density of mixture under the so-called quantum addition rule. We use the spectral…

Quantum Physics · Physics 2018-04-20 Lin Zhang , Jiamei Wang , Zhihua Chen

Magnetic resonance imaging of spin systems combines scientific applications in medicine, chemistry and physics. Here, we investigate the pixel-wise coherent quantum dynamics of spins consisting of a 40 by 40 micron sized region of interest…

We discuss a recently demonstrated type of microwave spectroscopy of trapped ultra-cold atoms known as "echo spectroscopy" [M.F. Andersen et. al., Phys. Rev. Lett., in press (2002)]. Echo spectroscopy can serve as an extremely sensitive…

Quantum Physics · Physics 2016-08-16 M. F. Andersen , A. Kaplan , T. Grünzweig , N. Davidson

Recently, sparsity-based algorithms are proposed for super-resolution spectrum estimation. However, to achieve adequately high resolution in real-world signal analysis, the dictionary atoms have to be close to each other in frequency,…

Machine Learning · Statistics 2015-06-05 Yiyuan She , Huanghuang Li , Jiangping Wang , Dapeng Wu

The estimation of land cover fractions from remote sensing images is a frequently used indicator of the environmental quality. This paper focuses on the quantification of land cover fractions in an urban area of Berlin, Germany, using…

Computer Vision and Pattern Recognition · Computer Science 2018-02-09 Lukas Drees , Ribana Roscher , Susanne Wenzel

We provide a description of interacting quantum fields in terms of density matrices for any occupation numbers in Fock space in a momentum basis. As a simple example, we focus on a real scalar field interacting with another real scalar…

High Energy Physics - Theory · Physics 2023-06-09 Christian Käding , Mario Pitschmann

We directly measured the normalized $\it{s}$-wave scattering cross-section of ultracold $^{40}\rm{K}$ atoms across a magnetic-field Feshbach resonance by colliding pairs of degenerate Fermi gases (DFGs) and imaging the scattered atoms. We…

We discuss strategies for quantum enhanced estimation of atomic transition frequencies with ions stored in Paul traps or neutral atoms trapped in optical lattices. We show that only marginal quantum improvements can be achieved using…

Quantum Physics · Physics 2012-04-23 U. Dorner

The energy spectrum of eigenvalues of the equal spin-spin interactions (ESSI) Hamiltonian has been found. The obtained spectrum is free from limitations imposed on number of spins and parameters of the ESSI Hamiltonian. This model can be…

Quantum Physics · Physics 2007-05-23 A. R. Kessel , R. R. Nigmatullin , N. M. Yakovleva

The atomization energies of molecules from first-principles density functional approximations improve from the local spin-density approximation (LSDA) to the Perdew-Burke-Ernzerhof (PBE)) generalized gradient approximation (GGA) to the…

Chemical Physics · Physics 2024-06-19 Shah Tanvir ur Rahman Chowdhury , John P. Perdew

Coherent Raman scattering spectroscopy is studied purposely, with the Gaussian ultrashort pulses as a hands-on elucidatory extraction tool of the clean coherent Raman resonant spectra from the overall measured data contaminated with the…

Optics · Physics 2017-04-05 Gombojav O. Ariunbold , Narangerel Altangerel

We consider the photoassociation of a low-density gas of quantum-degenerate trapped fermionic atoms into bosonic molecules in a spherically symmetric harmonic potential. For a dilute system and the photoassociation coupling energy small…

Mesoscale and Nanoscale Physics · Physics 2009-11-10 Takahiko Miyakawa , Pierre Meystre

This paper presents a numerical compression strategy for the boundary integral equation of acoustic scattering in two dimensions. These equations have oscillatory kernels that we represent in a basis of wave atoms, and compress by…

Numerical Analysis · Mathematics 2008-05-28 Laurent Demanet , Lexing Ying

Linear scaling density matrix methods typically do not provide individual eigenvectors and eigenvalues of the Fock/Kohn-Sham matrix, so additional work has to be performed if they are needed. Spectral transformation techniques facilitate…

Computational Physics · Physics 2018-01-15 Anastasia Kruchinina , Elias Rudberg , Emanuel H. Rubensson