Search results for "Dephasing"
showing 10 items of 73 documents
Non-Gaussian correlations imprinted by local dephasing in fermionic wires
2020
We study the behavior of an extended fermionic wire coupled to a local stochastic field. Since the quantum jump operator is Hermitian and quadratic in fermionic operators, it renders the model soluble, allowing investigation of the properties of the non-equilibrium steady-state and the role of dissipation-induced fluctuations. We derive a closed set of equations of motion solely for the two-point correlator; on the other hand, we find, surprisingly, that the many-body state exhibits non-Gaussian correlations. Density-density correlation function demonstrates a crossover from a regime of weak dissipation characterized by moderate heating and stimulated fluctuations to a quantum Zeno regime r…
Vibrational dephasing of νs (OH) in 2,4-dichlorophenol
1990
Abstract A quantitative analysis of the infrared bandshape of ν s (OH) in intramolecularly hydrogen-bonded 2,4-dichlorophenol in a series of solvents is presented. A distinct dependence of bandshape indices and relaxation parameters on the polarity of solvent has been found. The band shifts to lower wavenumbers, broadens and becomes more intense with increasing solvent polarity; correspondingly, the correlation function decays faster and the correlation time diminishes. The results are compared with those for previously studied systems. Factors influencing the bandshape are discussed.
Dephasing due to quasiparticle tunneling in fluxonium qubits: a phenomenological approach
2015
The fluxonium qubit has arisen as one of the most promising candidate devices for implementing quantum information in superconducting devices, since it is both insensitive to charge noise (like flux qubits) and insensitive to flux noise (like charge qubits). Here, we investigate the stability of the quantum information to quasiparticle tunneling through a Josephson junction. Microscopically, this dephasing is due to the dependence of the quasiparticle transmission probability on the qubit state. We argue that on a phenomenological level the dephasing mechanism can be understood as originating from heat currents, which are flowing in the device due to possible effective temperature gradients…
Optimized adiabatic passage with dephasing
2008
We study adiabatic population transfer with dephasing in two-level models driven by a chirped driving field. We show that the population transfer is maximized when the dynamics follows specific ellipses as trajectories in the parameter space. We determine the optimal parameters and estimate the losses in a closed form. These estimates show a similar robustness as for the standard lossless adiabatic processes with respect to variations of the parameters.
Hot-Carrier Generation in Plasmonic Nanoparticles: The Importance of Atomic Structure
2020
Metal nanoparticles are attractive for plasmon-enhanced generation of hot carriers, which may be harnessed in photochemical reactions. In this work, we analyze the coherent femtosecond dynamics of photon absorption, plasmon formation, and subsequent hot-carrier generation through plasmon dephasing using first-principles simulations. We predict the energetic and spatial hot-carrier distributions in small metal nanoparticles and show that the distribution of hot electrons is very sensitive to the local structure. Our results show that surface sites exhibit enhanced hot-electron generation in comparison to the bulk of the nanoparticle. While the details of the distribution depend on particle s…
Plasmon damping depends on the chemical nature of the nanoparticle interface
2019
Damping of gold nanorod plasmons by surface-adsorbed molecules is best explained by scattering off adsorbate-induced dipoles.
High-pressure Raman scattering of the stretching mode in nitrogen along the 300-K isotherm
1996
We present Raman scattering studies of the vibrational band of nitrogen at room temperature between 1 and 31 GPa allowing a detailed line-shape analysis. For the fluid and \ensuremath{\beta} phases the vibrational linewidths compare to dephasing rates ${\mathit{T}}_{2}^{\mathrm{\ensuremath{-}}1}$ determined by experiments in the time domain. The \ensuremath{\delta}-\ensuremath{\epsilon} transition is unmistakably marked by a drop of the vibrational linewidths around 17 GPa. A further transition into the \ensuremath{\eta} phase around 20 GPa proposed from previous Raman results can be ruled out. Additionally, clear evidence is found for a dynamical freezing of the ${\mathrm{N}}_{2}$ molecule…
Electromagnetically Induced Transparency and optical pumping processes formed in Cs sub-micron thin cell
2012
Abstract The Electromagnetically Induced Transparency (EIT) effect in a Λ -system formed by Cs atoms (6 S 1/2 − 6 P 3/2 − 6 S 1/2 ) confined in an extremely thin cell (ETC) (atomic column thickness L varies in the range of 800 nm –3 µm is studied both experimentally and theoretically. It is demonstrated that when the coupling laser frequency is in exact resonance with the corresponding atomic transition, the EIT resonance parameters weakly depend on L , which allows us to detect the effect at L = λ = 852 nm. EIT process reveals a striking peculiarity in case of the coupling laser detuned by Δ from the atomic transition, namely the width of the EIT resonance rapidly increases upon an in…
About the dynamics of strongly coupled surface plasmon polaritons and Sulforhodamine 101
2014
We investigate the dynamics of strongly coupled surface plasmon polaritons (SPP) and molecular excitations (ME) of Sulforhodamine 101 dye. The SPPs are excited by prism coupling technique on a thin silver film with dye molecules embedded in a polymer layer on top of it. Rabi splittings with energies of 135 and 97 meV are observed in the recorded dispersion relations. Both coupled oscillator model and transfer matrix method are used to fit the experimental results. In addition to the common reflectance measurements, polarization resolved detection of scattered signal from the molecular side is also utilized. Simultaneous detection of the scattered polaritons and molecular fluorescence reveal…
Entanglement control via reservoir engineering in ultracold atomic gases
2013
We study the entanglement of two impurity qubits immersed in a Bose-Einstein condensate (BEC) reservoir. This open quantum system is particularly interesting because the reservoir and system parameters are easily controllable and the reduced dynamics is highly non-Markovian. We show how the model allows for interpolation between a common dephasing scenario and an independent dephasing scenario by simply modifying the wavelength of the superlattice superposed to the BEC, and how this influences the dynamical properties of the impurities. We demonstrate the existence of very rich entanglement dynamics correspondent to different values of reservoir parameters, including phenomena such as entan…