Crystallographic point and space group symmetries in the one-and two-body density of crystals and generalized Patterson functions: Fourier path integral Monte Carlo case studies of novel high-temperature/high-pressure 4He quantum crystals

2003 ◽  
Vol 218 (10) ◽  
Author(s):  
Klaus A. Gernoth
Keyword(s):  
High Pressure ◽  
Monte Carlo ◽  
Formal Analysis ◽  
Body Density ◽  
Path Integral Monte Carlo ◽  
Space Group ◽  
Quantum Crystals ◽  
The One ◽  
Group Symmetries ◽  
High Temperature High Pressure

AbstractWe present a complete formal analysis of crystallographic point and space group symmetries in the local one- and two-body density

scholarly journals Improved Monte Carlo estimators for the one-body density

2007 ◽  
Vol 75 (3) ◽  
Author(s):  
Roland Assaraf ◽  
Michel Caffarel ◽  
Anthony Scemama
Keyword(s):  
Monte Carlo ◽  
Body Density ◽  
The One

scholarly journals Quantum Monte Carlo calculations of the one-body density matrix and excitation energies of silicon

1998 ◽  
Vol 57 (24) ◽  
pp. 15293-15302 ◽  
Author(s):  
P. R. C. Kent ◽  
Randolph Q. Hood ◽  
M. D. Towler ◽  
R. J. Needs ◽  
G. Rajagopal
Keyword(s):  
Monte Carlo ◽  
Density Matrix ◽  
Quantum Monte Carlo ◽  
Body Density ◽  
Excitation Energies ◽  
Monte Carlo Calculations ◽  
The One

QUANTUM MONTE CARLO STUDY OF THE GROUND-STATE PROPERTIES OF A FERMI GAS IN THE BCS-BEC CROSSOVER

2006 ◽  
Vol 20 (30n31) ◽  
pp. 5189-5198
Author(s):  
S. GIORGINI ◽  
G. E. ASTRAKHARCHIK ◽  
J. BORONAT ◽  
J. CASULLERAS
Keyword(s):  
Monte Carlo ◽  
Density Matrix ◽  
Ground State ◽  
Interaction Strength ◽  
Fermi Gas ◽  
Unitary Limit ◽  
Body Density ◽  
Ground State Properties ◽  
Wide Range ◽  
The One

The ground-state properties of a two-component Fermi gas with attractive short-range interactions are calculated using the fixed-node diffusion Monte Carlo method. The interaction strength is varied over a wide range by tuning the value a of the s-wave scattering length of the two-body potential. We calculate the energy per particle, the one- and two-body density matrix as a function of the interaction strength. Results for the momentum distribution of the atoms, as obtained from the Fourier transform of the one-body density matrix, are reported as a function of the interaction strength. Off-diagonal long-range order in the system is investigated through the asymptotic behavior of the two-body density matrix. The condensate fraction of pairs is calculated in the unitary limit and on both sides of the BCS-BEC crossover.

scholarly journals Crystal and electronic structure engineering of tin monoxide by external pressure

2021 ◽  
Author(s):  
Kun Li ◽  
Junjie Wang ◽  
Vladislav A. Blatov ◽  
Yutong Gong ◽  
Naoto Umezawa ◽  
...  
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Band Gap ◽  
High Pressures ◽  
Low Pressure ◽  
Widespread Application ◽  
Space Group ◽  
Tin Monoxide ◽  
High Possibility ◽  
Pressure Phase

AbstractAlthough tin monoxide (SnO) is an interesting compound due to its p-type conductivity, a widespread application of SnO has been limited by its narrow band gap of 0.7 eV. In this work, we theoretically investigate the structural and electronic properties of several SnO phases under high pressures through employing van der Waals (vdW) functionals. Our calculations reveal that a metastable SnO (β-SnO), which possesses space group P21/c and a wide band gap of 1.9 eV, is more stable than α-SnO at pressures higher than 80 GPa. Moreover, a stable (space group P2/c) and a metastable (space group Pnma) phases of SnO appear at pressures higher than 120 GPa. Energy and topological analyses show that P2/c-SnO has a high possibility to directly transform to β-SnO at around 120 GPa. Our work also reveals that β-SnO is a necessary intermediate state between high-pressure phase Pnma-SnO and low-pressure phase α-SnO for the phase transition path Pnma-SnO →β-SnO → α-SnO. Two phase transition analyses indicate that there is a high possibility to synthesize β-SnO under high-pressure conditions and have it remain stable under normal pressure. Finally, our study reveals that the conductive property of β-SnO can be engineered in a low-pressure range (0–9 GPa) through a semiconductor-to-metal transition, while maintaining transparency in the visible light range.

scholarly journals Multianvil High-Pressure/High-Temperature Synthesis and Characterization of multiferroic HP-Co3TeO6

2021 ◽  
Author(s):  
Gunter Heymann ◽  
Elisabeth Selb ◽  
Toni Buttlar ◽  
Oliver Janka ◽  
Martina Tribus ◽  
...  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Type Structure ◽  
Synthesis And Characterization ◽  
Temperature Synthesis ◽  
Space Group ◽  
Crystal System ◽  
High Temperature Synthesis ◽  
High Pressure High Temperature

By high-pressure/high-temperature multianvil synthesis a new high-pressure (HP) phase of Co3TeO6 was obtained. The compound crystallizes in the acentric trigonal crystal system of the Ni3TeO6-type structure with space group R3...

scholarly journals Two-term expansion of the ground state one-body density matrix of a mean-field Bose gas

2021 ◽  
Vol 60 (3) ◽  
Author(s):  
Phan Thành Nam ◽  
Marcin Napiórkowski
Keyword(s):  
Density Matrix ◽  
Ground State ◽  
Mean Field ◽  
Interaction Strength ◽  
Bose Gas ◽  
Body Density ◽  
The Mean ◽  
The One ◽  
Mean Field Regime ◽  
Number Of Particles

AbstractWe consider the homogeneous Bose gas on a unit torus in the mean-field regime when the interaction strength is proportional to the inverse of the particle number. In the limit when the number of particles becomes large, we derive a two-term expansion of the one-body density matrix of the ground state. The proof is based on a cubic correction to Bogoliubov’s approximation of the ground state energy and the ground state.

scholarly journals A fractional generalization of the dirichlet distribution and related distributions

2021 ◽  
Vol 24 (1) ◽  
pp. 112-136
Author(s):  
Elvira Di Nardo ◽  
Federico Polito ◽  
Enrico Scalas
Keyword(s):  
Monte Carlo ◽  
Probability Density Function ◽  
Monte Carlo Simulations ◽  
Probability Density ◽  
Dirichlet Distribution ◽  
One Dimensional ◽  
Reasonable Approximation ◽  
Generalized Dirichlet Distribution ◽  
The One ◽  
Generalized Dirichlet

Abstract This paper is devoted to a fractional generalization of the Dirichlet distribution. The form of the multivariate distribution is derived assuming that the n partitions of the interval [0, Wn ] are independent and identically distributed random variables following the generalized Mittag-Leffler distribution. The expected value and variance of the one-dimensional marginal are derived as well as the form of its probability density function. A related generalized Dirichlet distribution is studied that provides a reasonable approximation for some values of the parameters. The relation between this distribution and other generalizations of the Dirichlet distribution is discussed. Monte Carlo simulations of the one-dimensional marginals for both distributions are presented.

scholarly journals Symmetries and anomalies of (1+1)d theories: 2-groups and symmetry fractionalization

2021 ◽  
Vol 2021 (8) ◽  
Author(s):  
Matthew Yu
Keyword(s):  
Spectral Sequence ◽  
Global Symmetries ◽  
Group Symmetry ◽  
Low Dimension ◽  
The One ◽  
Group Symmetries

Abstract We investigate the interactions of discrete zero-form and one-form global symmetries in (1+1)d theories. Focus is put on the interactions that the symmetries can have on each other, which in this low dimension result in 2-group symmetries or symmetry fractionalization. A large part of the discussion will be to understand a major feature in (1+1)d: the multiple sectors into which a theory decomposes. We perform gauging of the one-form symmetry, and remark on the effects this has on our theories, especially in the case when there is a global 2-group symmetry. We also implement the spectral sequence to calculate anomalies for the 2-group theories and symmetry fractionalized theory in the bosonic and fermionic cases. Lastly, we discuss topological manipulations on the operators which implement the symmetries, and draw insights on the (1+1)d effects of such manipulations by coupling to a bulk (2+1)d theory.

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