scholarly journals Hidden Pseudogap and Excitation Spectra in a Strongly Coupled Two-Band Superfluid/Superconductor

2021 ◽  
Vol 6 (1) ◽  
pp. 8
Author(s):  
Hiroyuki Tajima ◽  
Pierbiagio Pieri ◽  
Andrea Perali
Keyword(s):  
Single Particle ◽  
Particle Density ◽  
Scanning Tunneling ◽  
Einstein Condensation ◽  
Tunneling Microscopy ◽  
Excitation Spectra ◽  
Strongly Coupled ◽  
Single Particle Density ◽  
The Many ◽  
Bose Einstein

We investigate single-particle excitation properties in the normal state of a two-band superconductor or superfluid throughout the Bardeen–Cooper–Schrieffer (BCS) to Bose–Einstein-condensation (BEC) crossover, within the many-body T-matrix approximation for multichannel pairing fluctuations. We address the single-particle density of states and the spectral functions consisting of two contributions associated with a weakly interacting deep band and a strongly interacting shallow band, relevant for iron-based multiband superconductors and multicomponent fermionic superfluids. We show how the pseudogap state in the shallow band is hidden by the deep band contribution throughout the two-band BCS-BEC crossover. Our results could explain the missing pseudogap in recent scanning tunneling microscopy experiments in FeSe superconductors.

The role of single-particle density in chemistry

1981 ◽  
Vol 53 (1) ◽  
pp. 95-126 ◽  
Author(s):  
Anjuli S. Bamzai ◽  
B. M. Deb
Keyword(s):  
Single Particle ◽  
Particle Density ◽  
Single Particle Density

A SOLVABLE MODEL OF INTERACTING MANY BODY SYSTEMS EXHIBITING A BREAKDOWN OF THE BOLTZMANN EQUATION

2014 ◽  
Vol 28 (03) ◽  
pp. 1450046
Author(s):  
B. H. J. McKELLAR
Keyword(s):  
Boltzmann Equation ◽  
Time Dependence ◽  
Single Particle ◽  
Density Operator ◽  
Particle Density ◽  
Solvable Model ◽  
Many Body ◽  
Single Particle Density ◽  
The Boltzmann Equation ◽  
Many Body Systems

In a particular exactly solvable model of an interacting system, the Boltzmann equation predicts a constant single particle density operator, whereas the exact solution gives a single particle density operator with a nontrivial time dependence. All of the time dependence of the single particle density operator is generated by the correlations.

VALIDITY OF THE BOGOLIUBOV APPROXIMATION FOR THE BOSE-EINSTEIN CONDENSATION IN A TRAP

2012 ◽  
Vol 17 ◽  
pp. 140-148 ◽  
Author(s):  
HIROSHI EZAWA ◽  
KEIJI WATANABE ◽  
KOICHI NAKAMURA
Keyword(s):  
Single Particle ◽  
The State ◽  
Trapping Potential ◽  
Einstein Condensation ◽  
Bose Einstein Condensation ◽  
Single Particle Level ◽  
Bogoliubov Approximation ◽  
Particle Level ◽  
Particle Potential ◽  
Bose Einstein

In treating system of bosons localized in a trapping potential, having a macroscopic number N0 of them condensing at the lowest single-particle level v0, Bogoliubov approximation is to replace the creation/annihilation operators [Formula: see text] of the state v0 by [Formula: see text]. We show that this approximation is justified if the inter-particle potential is repulsive in the sense specified. In fact, we show, by using [Formula: see text], that [Formula: see text] is effectively of the order [Formula: see text] under the condition stated.

132Te and single-particle density-dependent pairing

2009 ◽  
pp. 389-390
Author(s):  
N. V. Zamfir ◽  
R. O. Hughes ◽  
R. F. Casten ◽  
D. C. Radford ◽  
C. J. Barton ◽  
...  
Keyword(s):  
Single Particle ◽  
Particle Density ◽  
Density Dependent ◽  
Single Particle Density

scholarly journals Valley interference and spin exchange at the atomic scale in silicon

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
B. Voisin ◽  
J. Bocquel ◽  
A. Tankasala ◽  
M. Usman ◽  
J. Salfi ◽  
...  
Keyword(s):  
Spin Exchange ◽  
Atomic Scale ◽  
Scanning Tunneling ◽  
Coulomb Interactions ◽  
Tunneling Microscopy ◽  
Quantum Process ◽  
Strongly Coupled ◽  
Heisenberg Spin ◽  
Heisenberg Spin Exchange ◽  
Complex Phenomena

AbstractTunneling is a fundamental quantum process with no classical equivalent, which can compete with Coulomb interactions to give rise to complex phenomena. Phosphorus dopants in silicon can be placed with atomic precision to address the different regimes arising from this competition. However, they exploit wavefunctions relying on crystal band symmetries, which tunneling interactions are inherently sensitive to. Here we directly image lattice-aperiodic valley interference between coupled atoms in silicon using scanning tunneling microscopy. Our atomistic analysis unveils the role of envelope anisotropy, valley interference and dopant placement on the Heisenberg spin exchange interaction. We find that the exchange can become immune to valley interference by engineering in-plane dopant placement along specific crystallographic directions. A vacuum-like behaviour is recovered, where the exchange is maximised to the overlap between the donor orbitals, and pair-to-pair variations limited to a factor of less than 10 considering the accuracy in dopant positioning. This robustness remains over a large range of distances, from the strongly Coulomb interacting regime relevant for high-fidelity quantum computation to strongly coupled donor arrays of interest for quantum simulation in silicon.

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