Microscopic Theory of Linear Absorption and Fluorescence

2014 ◽  
pp. 295-314
Keyword(s):  
Microscopic Theory ◽  
Linear Absorption

scholarly journals Shaping Dynamical Casimir Photons

Universe ◽  
2021 ◽  
Vol 7 (6) ◽  
pp. 189
Author(s):  
Diego A. R. Dalvit ◽  
Wilton J. M. Kort-Kamp
Keyword(s):  
Optical Properties ◽  
Lattice Structure ◽  
Casimir Effect ◽  
Surface Profile ◽  
Microscopic Theory ◽  
Space Time ◽  
Quantum Vacuum ◽  
Dynamical Casimir Effect ◽  
Photon Pairs ◽  
Time Quantum

Temporal modulation of the quantum vacuum through fast motion of a neutral body or fast changes of its optical properties is known to promote virtual into real photons, the so-called dynamical Casimir effect. Empowering modulation protocols with spatial control could enable the shaping of spectral, spatial, spin, and entanglement properties of the emitted photon pairs. Space–time quantum metasurfaces have been proposed as a platform to realize this physics via modulation of their optical properties. Here, we report the mechanical analog of this phenomenon by considering systems in which the lattice structure undergoes modulation in space and in time. We develop a microscopic theory that applies both to moving mirrors with a modulated surface profile and atomic array meta-mirrors with perturbed lattice configuration. Spatiotemporal modulation enables motion-induced generation of co- and cross-polarized photon pairs that feature frequency-linear momentum entanglement as well as vortex photon pairs featuring frequency-angular momentum entanglement. The proposed space–time dynamical Casimir effect can be interpreted as induced dynamical asymmetry in the quantum vacuum.

scholarly journals Microscopic theory for coupled atomistic magnetization and lattice dynamics

2017 ◽  
Vol 1 (7) ◽  
Author(s):  
J. Fransson ◽  
D. Thonig ◽  
P. F. Bessarab ◽  
S. Bhattacharjee ◽  
J. Hellsvik ◽  
...  
Keyword(s):  
Lattice Dynamics ◽  
Microscopic Theory

scholarly journals Tuning nonlinear damping in graphene nanoresonators by parametric–direct internal resonance

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ata Keşkekler ◽  
Oriel Shoshani ◽  
Martin Lee ◽  
Herre S. J. van der Zant ◽  
Peter G. Steeneken ◽  
...  
Keyword(s):  
Parametric Resonance ◽  
Internal Resonance ◽  
Microscopic Theory ◽  
Fold Increase ◽  
Nonlinear Damping ◽  
Supporting Evidence ◽  
Nonlinear Dissipation ◽  
Modal Interactions ◽  
Solid State Physics ◽  
Internal Resonances

AbstractMechanical sources of nonlinear damping play a central role in modern physics, from solid-state physics to thermodynamics. The microscopic theory of mechanical dissipation suggests that nonlinear damping of a resonant mode can be strongly enhanced when it is coupled to a vibration mode that is close to twice its resonance frequency. To date, no experimental evidence of this enhancement has been realized. In this letter, we experimentally show that nanoresonators driven into parametric-direct internal resonance provide supporting evidence for the microscopic theory of nonlinear dissipation. By regulating the drive level, we tune the parametric resonance of a graphene nanodrum over a range of 40–70 MHz to reach successive two-to-one internal resonances, leading to a nearly two-fold increase of the nonlinear damping. Our study opens up a route towards utilizing modal interactions and parametric resonance to realize resonators with engineered nonlinear dissipation over wide frequency range.

scholarly journals From sources to initial data and back again: on bulk singularities in Euclidean AdS/CFT

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Alexandre Belin ◽  
Benjamin Withers
Keyword(s):  
Quantum Theory ◽  
Initial Data ◽  
Path Integral ◽  
Coherent States ◽  
Microscopic Theory ◽  
Delta Function ◽  
Common Method ◽  
Single Trace

Abstract A common method to prepare states in AdS/CFT is to perform the Euclidean path integral with sources turned on for single-trace operators. These states can be interpreted as coherent states of the bulk quantum theory associated to Lorentzian initial data on a Cauchy slice. In this paper, we discuss the extent to which arbitrary initial data can be obtained in this way. We show that the initial data must be analytic and define the subset of it that can be prepared by imposing bulk regularity. Turning this around, we show that for generic analytic initial data the corresponding Euclidean section contains singularities coming from delta function sources in the bulk. We propose an interpretation of these singularities as non-perturbative objects in the microscopic theory.

scholarly journals Zilch vortical effect for fermions

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Artem Alexandrov ◽  
Pavel Mitkin
Keyword(s):  
Kinetic Theory ◽  
Spin Polarization ◽  
Wigner Function ◽  
Microscopic Theory ◽  
Chiral Media ◽  
Function Formalism ◽  
Chiral Effects ◽  
Definition Of ◽  
Theory Framework ◽  
Full Analogy

Abstract We consider the notion of zilch current that was recently discussed in the literature as an alternative helicity measure for photons. Developing this idea, we suggest the generalization of the zilch for the systems of fermions. We start with the definition of the photonic zilch current in chiral kinetic theory framework and work out field-theoretical definition of the fermionic zilch using the Wigner function formalism. This object has similar properties to the photonic zilch and is conserved in the non-interacting theory. We also show that, in full analogy with a case of photons, the fermionic zilch acquires a non-trivial contribution due to the medium rotation - zilch vortical effect (ZVE) for fermions. Combined with a previously studied ZVE for photons, these results form a wider set of chiral effects parameterized by the spin of the particles and the spin of the current. We briefly discuss the origin of the ZVE, its possible relation to the anomalies in the underlying microscopic theory and possible application for studying the spin polarization in chiral media.

Microscopic theory of brownian motion

1975 ◽  
Vol 81 (4) ◽  
pp. 509-521 ◽  
Author(s):  
James T. Hynes ◽  
Raymond Kapral ◽  
Michael Weinberg
Keyword(s):  
Brownian Motion ◽  
Microscopic Theory
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