scholarly journals Driving chemical reactions with polariton condensates

2021 ◽  
Author(s):  
Sindhana Pannir-Sivajothi ◽  
Jorge Campos-Gonzalez-Angulo ◽  
Luis Martínez-Martínez ◽  
Shubham Sinha ◽  
Joel Yuen-Zhou
Keyword(s):  
Chemical Reactions ◽  
Einstein Condensation ◽  
Reaction Yield ◽  
Energy Redistribution ◽  
Activation Barriers ◽  
Laser Sources ◽  
Infrared Laser Sources ◽  
The Many ◽  
Electron Transfer Processes ◽  
Bose Einstein

Abstract When molecular transitions strongly couple to photon modes, they form hybrid light-matter modes called polaritons. Collective vibrational strong coupling is a promising avenue for control of chemistry, but this can be deterred by the large number of quasi-degenerate dark modes. The macroscopic occupation of a single polariton mode by excitations, as observed in Bose-Einstein condensation, offers promise for overcoming this issue. Here we theoretically investigate the effect of vibrational polariton condensation on the kinetics of electron transfer processes. Compared with excitation with infrared laser sources, the condensate changes the reaction yield significantly due to additional channels with reduced activation barriers resulting from the large accumulation of energy in the lower polariton, and the many modes available for energy redistribution during the reaction. Our results offer tantalizing opportunities to use condensates for driving chemical reactions, kinetically bypassing usual constraints of fast intramolecular vibrational redistribution in condensed phase.

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.

scholarly journals Beyond mean-field dynamics in closed and open bosonic systems

2013 ◽  
Author(s):  
Γεώργιος Κορδάς
Keyword(s):  
Mean Field ◽  
Einstein Condensation ◽  
Many Body ◽  
Practical Applications ◽  
Body Dynamics ◽  
Systematic Development ◽  
The Many ◽  
Bose Einstein ◽  
State Path ◽  
Present Thesis

The present thesis is devoted to the dynamics in open or closed manybodybosonic systems, with the use of beyond mean-eld methods.In the rst part, inspired by the state-of-the-art experiments, we study thedynamics of a Bose-Einstein condensation which is loaded in an optical latticewith localized loss channels for the atoms. We prove that the particularform of the dissipation can help us to control the many-body dynamics. Theloss allows the local manipulation of the system's coherence properties andcreates attractive xed points in the classical (mean-eld) phase space. Wepredict the dynamical creation of stable nonlinear structures like discretebright and dark solitons. Furthermore, for specic initial states, the systemsproduces highly entangled and long-living states, which are of high relevancefor practical applications. The rst part of this thesis ends with the study ofnon-equilibrium bosonic transport across optical one-dimensional lattices.In the second part, we present techniques for bosonic many-body systemswhich are based on path integrals. We analyze the Bose-Einstein condensationphenomenon by using tools from quantum information theory and eldtheory. Finally, we introduce a coherent state path integral formalism inthe continuum, which allows us the systematic development of approximatemethods for the study of bosons in optical lattices.

PAIRING OF HOLES INDUCED BY MAGNETIC INTERACTIONS

1988 ◽  
Vol 02 (05) ◽  
pp. 803-810
Author(s):  
D. Schmeltzer
Keyword(s):  
Critical Temperature ◽  
Hole Concentration ◽  
Magnetic Interaction ◽  
Magnetic Interactions ◽  
Einstein Condensation ◽  
Condensation Temperature ◽  
Many Body ◽  
Large Hole ◽  
The Many ◽  
Bose Einstein

We consider a planar Hubbard model with three sites per primitive cell. This model is mapped into a magnetic Hamiltonian. The charged holes interact via the magnetic interaction. The effect of this interaction is to create a magnetic background for the holes. Defining new quasi-particles we find that the many-body interaction becomes attractive and gives rise to conventional superconductivity. At large hole concentrations the critical temperature is determined by the antiferromagnetic exchange between copper-copper. In addition, the Increase of hole concentration reduces the exchange coupling which vanishes at some critical values. At small hole concentrations the critical temperature is determined by the Bose Einstein condensation temperature.

scholarly journals Functional renormalization for the Bardeen–Cooper–Schrieffer to Bose–Einstein condensation crossover

2011 ◽  
Vol 369 (1946) ◽  
pp. 2779-2799 ◽  
Author(s):  
Michael M. Scherer ◽  
Stefan Floerchinger ◽  
Holger Gies
Keyword(s):  
Scattering Length ◽  
Einstein Condensation ◽  
Many Body ◽  
Derivative Expansion ◽  
Functional Renormalization Group ◽  
Bose Einstein Condensation ◽  
Fermionic Atoms ◽  
Large Length ◽  
The Many ◽  
Bose Einstein

We review the functional renormalization group (RG) approach to the Bardeen–Cooper–Schrieffer to Bose–Einstein condensation (BCS–BEC) crossover for an ultracold gas of fermionic atoms. Formulated in terms of a scale-dependent effective action, the functional RG interpolates continuously between the atomic or molecular microphysics and the macroscopic physics on large length scales. We concentrate on the discussion of the phase diagram as a function of the scattering length and the temperature, which is a paradigm example for the non-perturbative power of the functional RG. A systematic derivative expansion provides for both a description of the many-body physics and its expected universal features as well as an accurate account of the few-body physics and the associated BEC and BCS limits.

QUANTUM KINETIC THEORY FOR A BOSE-EINSTEIN CONDENSED ALKALI GAS

2001 ◽  
Vol 15 (10n11) ◽  
pp. 1641-1650
Author(s):  
M. J. HOLLAND ◽  
J. COOPER ◽  
R. WALSER
Keyword(s):  
Quantum Correlations ◽  
Point Of View ◽  
Einstein Condensation ◽  
Theoretical Point ◽  
Equilibrium System ◽  
Many Body ◽  
Effective Interactions ◽  
Dilute Gas ◽  
The Many ◽  
Bose Einstein

The most salient features of the Bose-Einstein condensation of a magnetically confined alkali vapor is the diluteness of the gas and the extremely weak effective interactions. From a theoretical point of view, the interesting aspect is the potential formulation of the many-body quantum theory for a non-uniform and potentially non-equilibrium system founded entirely on microscopic physics. The crucial postulate is the rapid attenuation of many particle quantum correlations in the dilute system which can be motivated from universal considerations. In principle, it will be possible to provide direct comparison between theory and experiment over all temperature scales with no phenomenological parameters — a challenge facing the theoretical community in the near future. The dilute gas experiments provide an exciting stage on which to build bridges linking the theory of complex and collective phenomena in superconducting and superfluid systems, with the single particle microscopic physics described in quantum optics and laser physics.

Strong Coupling: Polariton Bose Condensation

2017 ◽  
Author(s):  
Alexey V. Kavokin ◽  
Jeremy J. Baumberg ◽  
Guillaume Malpuech ◽  
Fabrice P. Laussy
Keyword(s):  
Strong Coupling ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Dissipative System ◽  
Bose Condensation ◽  
Einstein Condensation ◽  
Strong Coupling Regime ◽  
Stimulated Scattering ◽  
Exciton Polaritons ◽  
Bose Einstein

In this Chapter we address the physics of Bose-Einstein condensation and its implications to a driven-dissipative system such as the polariton laser. We discuss the dynamics of exciton-polaritons non-resonantly pumped within a microcavity in the strong coupling regime. It is shown how the stimulated scattering of exciton-polaritons leads to formation of bosonic condensates that may be stable at elevated temperatures, including room temperature.

Systems with Condensates and Pairing

2018 ◽  
Author(s):  
Klaus Morawetz
Keyword(s):  
Critical Parameters ◽  
Einstein Condensation ◽  
Cooper Pairs ◽  
Pair Breaking ◽  
Systematic Theory ◽  
Bose Einstein Condensation ◽  
T Matrix ◽  
The Stability ◽  
Bose Einstein

The Bose–Einstein condensation and appearance of superfluidity and superconductivity are introduced from basic phenomena. A systematic theory based on the asymmetric expansion of chapter 11 is shown to correct the T-matrix from unphysical multiple-scattering events. The resulting generalised Soven scheme provides the Beliaev equations for Boson’s and the Nambu–Gorkov equations for fermions without the usage of anomalous and non-conserving propagators. This systematic theory allows calculating the fluctuations above and below the critical parameters. Gap equations and Bogoliubov–DeGennes equations are derived from this theory. Interacting Bose systems with finite temperatures are discussed with successively better approximations ranging from Bogoliubov and Popov up to corrected T-matrices. For superconductivity, the asymmetric theory leading to the corrected T-matrix allows for establishing the stability of the condensate and decides correctly about the pair-breaking mechanisms in contrast to conventional approaches. The relation between the correlated density from nonlocal kinetic theory and the density of Cooper pairs is shown.

scholarly journals Dynamics of the Creation of a Rotating Bose–Einstein Condensation by Two Photon Raman Transition Using a Laguerre–Gaussian Laser Pulse

Atoms ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 14
Author(s):  
Koushik Mukherjee ◽  
Soumik Bandyopadhyay ◽  
Dilip Angom ◽  
Andrew M. Martin ◽  
Sonjoy Majumder
Keyword(s):  
Interaction Strength ◽  
Transition Process ◽  
Laser Pulses ◽  
Harmonic Trap ◽  
Einstein Condensation ◽  
Raman Transition ◽  
Two Photon ◽  
Final Population ◽  
The Creation ◽  
Bose Einstein

We present numerical simulations to unravel the dynamics associated with the creation of a vortex in a Bose–Einstein condensate (BEC), from another nonrotating BEC using two-photon Raman transition with Gaussian (G) and Laguerre–Gaussian (LG) laser pulses. In particular, we consider BEC of Rb atoms at their hyperfine ground states confined in a quasi two dimensional harmonic trap. Optical dipole potentials created by G and LG laser pulses modify the harmonic trap in such a way that density patterns of the condensates during the Raman transition process depend on the sign of the generated vortex. We investigate the role played by the Raman coupling parameter manifested through dimensionless peak Rabi frequency and intercomponent interaction on the dynamics during the population transfer process and on the final population of the rotating condensate. During the Raman transition process, the two BECs tend to have larger overlap with each other for stronger intercomponent interaction strength.

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