Article
Physics, Multidisciplinary
Lukas Rammelmueller, David Huber, Matija Cufar, Joachim Brand, Hans-Werner Hammer, Artem G. Volosniev
Summary: We present a numerical analysis of spin-2 fermions in a one-dimensional harmonic potential in the presence of a magnetic point-like impurity. Ground-state level crossing between sectors with different fermion parities is observed already for a few particles, which indicates a few-body precursor of a quantum phase transition. This picture is further supported by analyzing density-density correlations in momentum space. Finally, we discuss the experimental realization of this system in existing cold-atoms platforms.
Article
Materials Science, Multidisciplinary
Joseph Kleinhenz, Igor Krivenko, Guy Cohen, Emanuel Gull
Summary: This article describes an experiment on the Kondo cloud, where the researchers examined the extent of the cloud in 1D by measuring the effect of nearby electrostatic perturbations on T-K. They also observed the Kondo state in the local density of states of the leads and made detailed predictions for future experiments.
Article
Physics, Multidisciplinary
Ni Ma, De-Yang Wang, Ben-Rui Huang, Kai-Yi Li, Jing-Peng Song, Jian-Zhong Liu, Hong-Ping Mei, Mao Ye, Ang Li
Summary: In this study, we used scanning tunneling microscopy to identify the chain-like structure and anisotropic electronic states on the surface of TaNiTe5. We found that even with chromium impurities deposited on the surface and a magnetic field applied normal to the surface, electron scatterings are largely suppressed. This makes TaNiTe5 a promising material for low-dissipation spintronic applications.
Article
Physics, Multidisciplinary
Meng Lyu, Hengcan Zhao, Jiahao Zhang, Zhen Wang, Shuai Zhang, Peijie Sun
Summary: Needle-like single crystals of CeAu2In4 have been grown and characterized as a new candidate of quasi-one-dimensional Kondo lattice compound, showing antiferromagnetic transition, Fermi liquid behavior, and a low Kondo temperature. The system exhibits similarities to YbNi4P2 and CeRh6Ge4 with a tunable ferromagnetic quantum critical point. CeAu2In4 appears to be an interesting model system for exploring antiferromagnetic quantum critical behaviors in a quasi-one-dimensional Kondo lattice with enhanced quantum fluctuations.
Article
Physics, Multidisciplinary
Mitchell J. Knight, Harry M. Quiney, Andy M. Martin
Summary: This paper describes the variational determination of the two-fermion reduced density matrix for harmonically trapped, ultracold few-fermion systems in one dimension with equal spin populations. The problem is formulated as a semi-definite program subject to N-representability conditions. The ground-state energies, density, pair-correlation function, and eigenvalues of the 2-RDM are found using an augmented Lagrangian method. The results show that this method accurately describes the salient features of the systems and has the potential to handle larger systems.
NEW JOURNAL OF PHYSICS
(2022)
Article
Optics
Damian Wlodzynski
Summary: A method for numerically exact calculation is proposed in this article for a mixture with a single impurity and several majority fermions in a harmonic potential. The method separates one degree of freedom through a tailored canonical transformation and performs exact diagonalization on the simplified Hamiltonian. This method is particularly effective for heavy impurities.
Article
Physics, Multidisciplinary
Maksim Tomchenko
Summary: In this study, exact solutions for a one-dimensional system of N = 2;3 spinless point bosons with zero boundary conditions are studied using Bethe ansatz. The density profile and nodal structure of the lowest states for different gamma values are obtained. The ideal crystal is found to correspond to specific quantum numbers when the coupling constant gamma is less than or equal to 1. The ground state of the system corresponds to a liquid state for any gamma and large N, and has a nodeless wave function.
JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL
(2022)
Article
Materials Science, Multidisciplinary
A. A. Zvyagin
Summary: The expectation value of the edge Majorana operator in a one-dimensional model of spinless fermions with nearest-neighbor interactions and open boundary conditions was calculated. It was found that this expectation value is formed by contributions from bulk states and localized edge modes.
Article
Optics
Jun-Cong Zheng, Peng-Bo LI
Summary: We investigated the transmission of single and two photons in a one-dimensional waveguide coupled with a Kerr micro-ring resonator and a polarized quantum emitter. The non-reciprocal behavior of the system is attributed to the unbalanced coupling between the quantum emitter and the resonator, causing a phase shift. Our analytical solutions and numerical simulations showed that the nonlinear resonator scattering leads to energy redistribution of the two photons through the bound state. In the two-photon resonance state, the polarization of the correlated photons is locked to their propagation direction, resulting in non-reciprocity. Hence, our configuration can function as an optical diode.
Article
Physics, Condensed Matter
J. S. Kim, G. R. Stewart
Summary: This study compares the changes in superconducting properties of two compounds with controlled impurity levels and finds that the superconducting properties of UBe13 are closely related to purity level, while LuBe13 samples show smaller changes in response to purity variations. These results are consistent with previous studies that support UBe13 as an unconventional superconductor and LuBe13 as a conventional BCS superconductor.
PHYSICA B-CONDENSED MATTER
(2022)
Article
Physics, Multidisciplinary
Alexander N. Gorban, Bogdan Grechuk, Evgeny M. Mirkes, Sergey Stasenko, Ivan Y. Tyukin
Summary: This work introduces a method for correcting Artificial Intelligence errors using external devices and new decisions for fast, non-iterative corrections, especially suitable for legacy AI systems. Through new stochastic separation theorems, corrections can be made to data with fine-grained structure.
Article
Physics, Applied
Yu-Hsun Chu, Hou-Ju Chen, Shin-Ye Lee, Christopher John Butler, Li-Syuan Lu, Han Yeh, Wen-Hao Chang, Minn-Tsong Lin
Summary: Researchers have studied the electronic structures of different types of MoS2 steps using scanning tunneling microscopy and spectroscopy. They found that each type has unique bandgap features, which can be modified by choosing different edge conditions.
APPLIED PHYSICS LETTERS
(2022)
Article
Mechanics
Tribikram Gupta, Kalpana Sharma, M. Lavanyaa, Sanjay Gupta
Summary: Graphene nanoribbons (GNRs) are widely used in nanoelectronics and opto-electronics. In this study, we investigated the energy spectrum and mapping of alternate bond systems in one-dimensional and quasi one-dimensional chains. Our findings provide valuable insights for the applications of GNRs.
Article
Materials Science, Multidisciplinary
Magdalena Foltyn, Dawid Pinkowicz, Michal Rams
Summary: Single crystal study reveals that Co(NCS)2(aniline)2 forms a canted AF magnetic structure at 6.49 K, which explains the hysteresis loop along the b crystal direction. The Ising spin system of Co(II) ions can be described by the J1-J2 triangular model. Specific heat analysis gives exchange interactions J1 = 31.3(4) K and 2J2 = -2.23(7) K. Application of magnetic field perpendicular to b compensates for AF exchange J2, allowing observation of magnetic relaxation of single chains.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2023)
Article
Physics, Multidisciplinary
M. C. Gordillo
Summary: The behavior of mixtures of Yb-173 and Yb-171 fermionic isotopes loaded in 1D optical lattices was studied using diffusion Monte Carlo technique to solve the Schrodinger equation. Different cluster behaviors were observed with varying interactions between pairs of fermions, showing both metallic-like and insulator-like states in the clusters.
NEW JOURNAL OF PHYSICS
(2021)
Article
Physics, Multidisciplinary
L. A. Reynolds, E. Schwartz, U. Ebling, M. Weyland, J. Brand, M. F. Andersen
PHYSICAL REVIEW LETTERS
(2020)
Article
Physics, Condensed Matter
Mingrui Yang, Matija Cufar, Elke Pahl, Joachim Brand
Summary: This study presents exact numerical data for the lowest-energy momentum eigenstates of a repulsive spin impurity in a one-dimensional Bose gas, and identifies different dynamical regimes and transitions between them based on the energies and correlation functions. The results reveal the behavior of impurities in different dynamical regimes and their transitions.
Article
Physics, Multidisciplinary
Ulrich Ebling, Ulrich Zulicke, Joachim Brand
Summary: We theoretically study a system of spin-1/2 fermions confined to two spatial dimensions and experiencing isotropic short-range attraction, with the presence of spin-orbit coupling and Zeeman spin splitting. We find that two-particle bound states have a dominant triplet contribution in a specific region of parameter space where the spin-splitting energy is large. The purest triplet character of the dimers is observed under weak s-wave interaction strength. The existence of bound states is determined by the center-of-mass momentum.
Article
Physics, Multidisciplinary
Kadin Thompson, Joachim Brand, Ulrich Zuelicke
Summary: A topological superfluid phase with emergent chiral -p-wave pair potential is investigated in a two-dimensional Fermi superfluid, where s-wave pairing, spin-orbit coupling, and a large Zeeman splitting are present. The subgap-energy bound states at step-like interfaces are studied using the spin-resolved Bogoliubov-de Gennes mean-field formalism and the Andreev approximation. The presence of Majorana zero modes and the effects of boundary conditions on their properties are analyzed.
Article
Optics
Sarthak Choudhury, Joachim Brand
Summary: The dynamics of a vortex molecule in two coherently coupled superfluids in a quasi-two-dimensional geometry were investigated, revealing internal dynamics such as rotation and boundary-induced breakup. Stable and unstable fixed points as well as separatrices characterizing the dynamics of the vortex molecule were classified.
Article
Materials Science, Multidisciplinary
Joachim Brand, Mingrui Yang, Elke Pahl
Summary: The study investigates a statistical bias in FCIQMC that can become the dominant error, especially in scenarios without sign problem, such as in bosonic systems. Researchers provide new insights into the nature of the bias and suggest possible methods to address the population control bias.
Article
Physics, Multidisciplinary
K. Thompson, U. Zulicke, J. Brand
Summary: This study investigates the coexistence of topological and nontopological superfluids in a two-dimensional spin-imbalanced Fermi gas using zero-temperature mean-field approach and exact numerical results, revealing the dependence of topological transition on the Zeeman spin-splitting energy. By controlling the strength of interactions and the spin energy, it is possible to spatially separate and coexist topological and nontopological superfluids.
PHYSICAL REVIEW RESEARCH
(2021)
Article
Physics, Multidisciplinary
Ulrich Ebling, Ali Alavi, Joachim Brand
Summary: This study explores the properties of the lowest energy states with nonzero total momentum (yrast states) in the Hubbard model, focusing on spin-1/2 fermions with attractive on-site interaction in a quantum ring configuration at low density. The transition from 1D to 2D regime is investigated using Bethe ansatz and Full-Configuration-Interaction Quantum Monte Carlo method to examine the changes in yrast excitation spectrum and the impact of pairing. Additionally, fragmented condensation signatures for certain yrast states typically associated with dark solitons are identified.
PHYSICAL REVIEW RESEARCH
(2021)
Article
Physics, Multidisciplinary
Peter Jeszenszki, Ulrich Ebling, Hongjun Luo, Ali Alavi, Joachim Brand
PHYSICAL REVIEW RESEARCH
(2020)
Article
Chemistry, Physical
Mingrui Yang, Elke Pahl, Joachim Brand
JOURNAL OF CHEMICAL PHYSICS
(2020)
Article
Optics
K. Thompson, J. Brand, U. Zuelicke
Article
Optics
Sophie S. Shamailov, Joachim Brand
Article
Optics
Peter Jeszenszki, Ali Alavi, Joachim Brand
Article
Optics
A. Munoz Mateo, V. Delgado, M. Guilleumas, R. Mayol, J. Brand
