12,550 research outputs found
Correlated two-photon transport in a one-dimensional waveguide side-coupled to a nonlinear cavity
We investigate the transport properties of two photons inside a
one-dimensional waveguide side-coupled to a single-mode nonlinear cavity. The
cavity is filled with a nonlinear Kerr medium. Based on the Laplace transform
method, we present analytic solution of quantum states of the transmitted and
reflected two photons, which are initially prepared in a Lorentzian wave
packet. The solution reveals how quantum correlation between the two photons
emerge after the scattering by the nonlinear cavity. In particular, we show
that the output wave function of the two photons in position space can be
localized in the relative coordinates, which is a feature that may be
interpreted as a two-photon bound state in this waveguide-cavity system.Comment: 9 pages, 5 figure
Parametric generation of quadrature squeezing of mirrors in cavity optomechanics
We propose a method to generate quadrature squeezed states of a moving mirror
in a Fabry-Perot cavity. This is achieved by exploiting the fact that when the
cavity is driven by an external field with a large detuning, the moving mirror
behaves as a parametric oscillator. We show that parametric resonance can be
reached approximately by modulating the driving field amplitude at a frequency
matching the frequency shift of the mirror. The parametric resonance leads to
an efficient generation of squeezing, which is limited by the thermal noise of
the environment.Comment: 4 pages, 2 figure
Spectrum of single-photon emission and scattering in cavity optomechanics
We present an analytic solution describing the quantum state of a single
photon after interacting with a moving mirror in a cavity. This includes
situations when the photon is initially stored in a cavity mode as well as when
the photon is injected into the cavity. In addition, we obtain the spectrum of
the output photon in the resolved-sideband limit, which reveals spectral
features of the single-photon strong-coupling regime in this system. We also
clarify the conditions under which the phonon sidebands are visible and the
photon-state frequency shift can be resolved.Comment: 5 pages, 5 figure
Correlated two-photon scattering in cavity optomechanics
We present an exact analytical solution of the two-photon scattering in a
cavity optomechanical system. This is achieved by solving the quantum dynamics
of the total system, including the optomechanical cavity and the cavity-field
environment, with the Laplace transform method. The long-time solution reveals
detailed physical processes involved as well as the corresponding resonant
photon frequencies. We characterize the photon correlation induced in the
scattering process by calculating the two-photon joint spectrum of the
long-time state. Clear evidence for photon frequency anti-correlation can be
observed in the joint spectrum. In addition, we calculate the equal-time
second-order correlation function of the cavity photons. The results show that
the radiation pressure coupling can induce photon blockade effect, which is
strongly modulated by the phonon sideband resonance. In particular, we obtain
an explicit expression of optomechanical coupling strength determining these
sideband modulation peaks based on the two-photon resonance condition.Comment: 10 pages, 6 figure
Majorana Fermion Induced Non-local Current Correlations in Spin-orbit Coupled Superconducting Wires
Recent observation of zero bias conductance peaks in semiconductor
wire/superconductor heterostructures has generated great interest, and there is
a hot debate on whether the observation is associated with Majorana fermions
(MFs). Here we study the local and crossed Andreev reflections in a junction of
two normal leads and a sandwiched superconductor-semiconductor wire with two
spatially separated but strongly coupled MF end states. The conductance and
Fano factors of such a device are sharply different from the topologically
trivial case even in the presence of disorder, and can hence be used to
identify MFs unambiguously.Comment: 7+ pages, 10 figure
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