Quantum Extension of the Jarzynski Relation

The relation between the distribution of work performed on a classical system by an external force switched on an arbitrary timescale, and the corresponding equilibrium free energy difference, is generalized to quantum systems. Using the adiabatic representation we show that this relation holds for isolated systems as well as for systems coupled to a bath described by a master equation. A close formal analogy is established between the present classical trajectory picture over populations of adiabatic states and phase fluctuations (dephasing) of a quantum coherence in spectral lineshapes, described by the stochastic Liouville equation

Comment on Quantum Interference between Light Sources Separated by 150 Million Kilometers Deng et al. PHYSICAL REVIEW LETTERS 123, 080401 (2019)

This is a comment on the paper : Quantum Interference between Light Sources Separated by 150 Million Kilometers by Deng et al, PHYSICAL REVIEW LETTERS 123, 080401 (2019

Generalized Coherent State Derivation of TDDFT Equations for Superconductors

Equations of motion are derived for the normal and the anomalous single-electron density matrices of a Fermi liquid using a time dependent finite temperature generalized coherent state (GCS) variational ansatz for the many-body density matrix. Self-consistent equations for the order parameter $\Delta$ allow to investigate the interplay of Coulomb repulsion and pairing attraction in homogeneous and inhomogeneous Fermi-liquids with spontaneously broken symmetry such as high temperature superconductors. The temperature of the Kosterlitz-Thouless transition to the two-dimensional superfluidity is calculated.Comment: 19 page

Fluctuation theorems for quantum master equations

A quantum fluctuation theorem for a driven quantum subsystem interacting with its environment is derived based solely on the assumption that its reduced density matrix obeys a closed evolution equation i.e. a quantum master equation (QME). Quantum trajectories and their associated entropy, heat and work appear naturally by transforming the QME to a time dependent Liouville space basis that diagonalizes the instantaneous reduced density matrix of the subsystem. A quantum integral fluctuation theorem, a steady state fluctuation theorem and the Jarzynski relation are derived in a similar way as for classical stochastic dynamics.Comment: Submitted to Phys. Rev.

Two-dimensional Infrared Spectroscopy of vibrational polaritons of molecules in an optical cavity

Strong coupling of molecular vibrations to an infrared cavity mode affects their nature by creating dressed polariton states. We show how the single and double vibrational polariton manifolds may be controlled by varying the cavity coupling strength, and probed by a time domain 2DIR technique, Double Quantum Coherence (DQC). Applications are made to the amide-I ($CO$) and amide-II ($CN$) bond vibrations of $N-methylacetamide$ (NMA).Comment: 16 pages, 6 figures, 1 tabl

Nonlinear transmission spectroscopy with dual frequency combs

We show how two frequency combs $\mathcal{E}_1$, $\mathcal{E}_2$ can be used to measure single-photon, two-photon absorption (TPA), and Raman resonances in a molecule with three electronic bands, by detecting the radio frequency modulation of the nonlinear transmission signal. Some peaks are independent of the carrier frequency of the comb and others shift with that frequency and have a width close to the comb width. TPA and Raman resonances independent of the carrier frequency are selected by measuring the transmission signal $\sim\mathcal{E}_1^2 \mathcal{E}_2^2$ and the single-photon resonances are selected by measuring the transmission signal $\sim\mathcal{E}_1^3\mathcal{E}_2$. Sinusoidal spectral phase shaping strongly affects the TPA, but not the Raman resonances.Comment: 13 pages, 11 Figure

Probing anomalous relaxation by coherent multidimensional optical spectroscopy

We propose to study the origin of algebraic decay of two-point correlation functions observed in glasses, proteins, and quantum dots by their nonlinear response to sequences of ultrafast laser pulses. Power-law spectral singularities and temporal relaxation in two-dimensional correlation spectroscopy (2DCS) signals are predicted for a continuous time random walk model of stochastic spectral jumps in a two level system with a power-law distribution of waiting times $\psi (t)\sim t^{-\alpha -1}$. Spectroscopic signatures of stationary ensembles for $1<\alpha <2$ and aging effects in nonstationary ensembles with $0<\alpha <1$ are identified