781 research outputs found
Strongly correlated two-photon transport in a one-dimensional waveguide coupled to a weakly nonlinear cavity
We study the photon-photon correlation properties of two-photon transport in
a one-dimensional waveguide coupled to a nonlinear cavity via a real-space
approach. It is shown that the intrinsic dissipation of the nonlinear cavity
has an important effect upon the correlation of the transported photons. More
importantly, strongly correlated photons can be obtained in the transmitted
photons even when the nonlinear interaction strength is weak in the cavity. The
strong photon-photon correlation is induced by the Fano resonance involving
destructive interference between the plane wave and bound state for two-photon
transport.Comment: 7 pages, 5 figure
Tunable photon statistics in weakly nonlinear photonic molecules
In recent studies [Liew et al., Phys. Rev. Lett. 104, 183601 (2010); Bamba et
al., Phys. Rev. A 83, 021802(R) (2011)], due to destructive interference
between different paths for two-photon excitation, strong photon antibunching
can be obtained in a photonic molecule consisting of two coupled cavity modes
with weak Kerr nonlinearity when one of the cavity modes is driven resonantly.
Here, we study the photon statistics in a nonlinear photonic molecule with both
the two cavity modes being driven coherently. We show that the statistical
properties of the photons can be controlled by regulating the coupling constant
between the cavity modes, the strength ratio and the relative phase between the
driving fields. The photonic molecules with two driven modes can be used to
generate tunable single-photon sources or controlled photonic quantum gates
with weak Kerr nonlinearity.Comment: 6 pages, 5 figure
Strong photon antibunching of symmetric and antisymmetric modes in weakly nonlinear photonic molecules
We study the photon statistics of symmetric and antisymmetric modes in a
photonic molecule consisting of two linearly coupled nonlinear cavity modes.
Our calculations show that strong photon antibunching of both symmetric and
antisymmetric modes can be obtained even when the nonlinearity in the photonic
molecule is weak. The strong antibunching effect results from the destructive
interference between different paths for two-photon excitation. Moreover, we
find that the optimal frequency detunings for strong photon antibunching in the
symmetric and antisymmetric modes are linearly dependent on the coupling
strength between the cavity modes in the photonic molecule. This implies that
the photonic molecules can be used to generate tunable single-photon sources by
tuning the values of the coupling strength between the cavity modes with weak
nonlinearity.Comment: 6 pages, 8 figure
Controllable optical output fields from an optomechanical system with a mechanical driving
We investigate the properties of the optical output fields from a cavity
optomechanical system, where the cavity is driven by a strong coupling and a
weak probe optical fields and the mechanical resonator is driven by a coherent
mechanical pump. When the frequency of the mechanical pump matches the
frequency difference between the coupling and probe optical fields, due to the
interference between the different optical components at the same frequency, we
demonstrate that the large positive or negative group delay of the output field
at the frequency of probe field can be achieved and tuned by adjusting the
phase and amplitude of the mechanical driving field. Moreover, the strength of
the output field at the frequency of optical four-wave-mixing (FWM) field also
can be controlled (enhanced and suppressed) by tuning the phase and amplitude
of the mechanical pump. We show that the power of the output field at the
frequency of the optical FWM field can be suppressed to zero or enhanced so
much that it can be comparable with and even larger than the power of the input
probe optical field.Comment: 7 pages, 9 figures. Comments are welcome
Optical nonreciprocity and optomechanical circulator in three-mode optomechanical systems
We demonstrate the possibility of optical nonreciprocal response in a
three-mode optomechanical system where one mechanical mode is optomechanically
coupled to two linearly coupled optical modes simultaneously. The optical
nonreciprocal behavior is induced by the phase difference between the two
optomechanical coupling rates which breaks the time-reversal symmetry of the
three-mode optomechanical system. Moreover, the three-mode optomechanical
system can also be used as a three-port circulator for two optical and one
mechanical modes, which we refer to as optomechanical circulator.Comment: 8 pages, 7 figure
Entangled state engineering of vibrational modes in a multi-membrane optomechanical system
We propose a method to generate entangled states of the vibrational modes of
N membranes which are coupled to a cavity mode via the radiation pressure.
Using sideband excitations, we show that arbitrary entangled states of
vibrational modes of different membranes can be produced in principle by
sequentially applying a series of classical pulses with desired frequencies,
phases and durations. As examples, we show how to synthesize several typical
entangled states, for example, Bell states, NOON states, GHZ states and W
states. The environmental effect, information leakage, and experimental
feasibility are briefly discussed. Our proposal can also be applied to other
experimental setups of optomechanical systems, in which many mechanical
resonators are coupled to a common sing-mode cavity field via the radiation
pressure.Comment: 15 pages, 10 figure
Phononic Josephson oscillation and self-trapping with two-phonon exchange interaction
We propose a bosonic Josephson junction (BJJ) in two nonlinear mechanical
resonator coupled through two-phonon exchange interaction induced by quadratic
optomechanical couplings. The nonlinear dynamic equations and effective
Hamiltonian are derived to describe behaviors of the BJJ. We show that the BJJ
can work in two different dynamical regimes: Josephson oscillation and
macroscopic self-trapping. The system can transfer from one regime to the other
one when the self-interaction and asymmetric parameters exceed their critical
values. We predict that a transition from Josephson oscillation to macroscopic
self-trapping can be induced by the phonon damping in the asymmetric BJJs. Our
results opens up a way to demonstrate BJJ with two-phonon exchange interaction
and can be applied to other systems, such as the optical and microwave systems.Comment: 7 pages, 7 figure
Renormalized quantum Fisher information manifestation of Berezinskii-Kosterlitz-Thouless phase transition for spin-1/2 XXZ chain
Combining the ideas of quantum Fisher information and quantum renormalization
group method, the Berezinskii-Kosterlitz-Thouless quantum phase transition of
spin- 1/2 XXZ chain is investigated. Quantum Fisher informations of the whole N
sites and the partial N/3 sites are studied. They display very similar
behaviors, even though their mathematical formulas are very different from each
other. The universally critical exponent of quantum Fisher information is
obtained as beta=0.47, which is consistent with the results obtained by the
renormalized concurrence or discord. We also discuss the relationship between
quantum Fisher information and entanglemen
Engineering of nonclassical motional states in optomechanical systems
We propose to synthesize arbitrary nonclassical motional states in
optomechanical systems by using sideband excitations and photon blockade. We
first demonstrate that the Hamiltonian of the optomechanical systems can be
reduced, in the strong single-photon optomechanical coupling regime when the
photon blockade occurs, to one describing the interaction between a driven
two-level trapped ion and the vibrating modes, and then show a method to
generate target states by using a series of classical pulses with desired
frequencies, phases, and durations. We further analyze the effect of the photon
leakage, due to small anharmonicity, on the fidelity of the expected motional
state, and study environment induced decoherence. Moreover, we also discuss the
experimental feasibility and provide operational parameters using the possible
experimental data.Comment: 11 pages, 4 figure
From blockade to transparency: controllable photon transmission through a circuit QED system
A strong photon-photon nonlinear interaction is a necessary condition for
photon blockade. Moreover, this nonlinearity can also result a bistable
behavior in the cavity field. We analyze the relation between detecting field
and photon blockade in a superconducting circuit QED system, and show that
photon blockade cannot occur when the detecting field is in the bistable
regime. This photon blockade is the microwave-photonics analog of the Coulomb
blockade. We further demonstrate that the photon transmission through such
system can be controlled (from photon blockade to transparency) by the
detecting field. Numerical calculations show that our proposal is
experimentally realizable with current technology.Comment: 7 papes, 5 figure
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