5,505 research outputs found
Generation of time-bin entangled photons without temporal post-selection
We report on the implementation of a new interferometric scheme that allows
the generation of photon pairs entangled in the time-energy degree of freedom.
This scheme does not require any kind of temporal post-selection on the
generated pairs and can be used even with lasers with short coherence time.Comment: RevTex, 6 pages, 8 figure
Complete and Deterministic discrimination of polarization Bell state assisted by momentum entanglement
A complete and deterministic Bell state measurement was realized by a simple
linear optics experimental scheme which adopts 2-photon polarization-momentum
hyperentanglement. The scheme, which is based on the discrimination among the
single photon Bell states of the hyperentangled state, requires the adoption of
standard single photon detectors. The four polarization Bell states have been
measured with average fidelity by using the linear momentum
degree of freedom as the ancilla. The feasibility of the scheme has been
characterized as a function of the purity of momentum entanglement.Comment: 4 pages, v2, comments adde
Self-steepening of light pulses
Self-steepening of light pulses due to propagation in medium with intensity-dependent index of refractio
"All-versus-nothing" nonlocality test of quantum mechanics by two-photon hyperentanglement
We report the experimental realization and the characterization of
polarization and momentum hyperentangled two photon states, generated by a new
parametric source of correlated photon pairs. By adoption of these states an
"all versus nothing" test of quantum mechanics was performed. The two photon
hyperentangled states are expected to find at an increasing rate a widespread
application in state engineering and quantum information. PACS: 03.65.Ud,
03.67.Mn, 42.65. LmComment: Replaced with published versio
Entanglement and Quantum Superposition of a Macroscopic - Macroscopic system
Two quantum Macro-states and their Macroscopic Quantum Superpositions (MQS)
localized in two far apart, space - like separated sites can be non-locally
correlated by any entangled couple of single-particles having interacted in the
past. This novel Macro - Macro paradigm is investigated on the basis of a
recent study on an entangled Micro-Macro system involving N=10^5 particles.
Crucial experimental issues as the violation of Bell's inequalities by the
Macro - Macro system are considered.Comment: 4 pages, 4 figure
Single photon generation by pulsed excitation of a single dipole
The fluorescence of a single dipole excited by an intense light pulse can
lead to the generation of another light pulse containing a single photon. The
influence of the duration and energy of the excitation pulse on the number of
photons in the fluorescence pulse is studied. The case of a two-level dipole
with strongly damped coherences is considered. The presence of a metastable
state leading to shelving is also investigated.Comment: 17 pages, 4 figures, submitted to PR
Spontaneous and stimulated emission tuning characteristics of a Josephson junction in a microcavity
We have investigated theoretically the tuning characteristics of a Josephson
junction within a microcavity for one-photon spontaneous emission and for
one-photon and two-photon stimulated emission. For spontaneous emission, we
have established the linear relationship between the magnetic induction and the
voltage needed to tune the system to emit at resonant frequencies. For
stimulated emission, we have found an oscillatory dependence of the emission
rate on the initial Cooper pair phase difference and the phase of the applied
field. Under specific conditions, we have also calculated the values of the
applied radiation amplitude for the first few emission maxima of the system and
for the first five junction-cavity resonances for each process. Since the
emission of photons can be controlled, it may be possible to use such a system
to produce photons on demand. Such sources will have applications in the fields
of quantum cryptography, communications and computation
Quantum information distributors: Quantum network for symmetric and asymmetric cloning in arbitrary dimension and continuous limit
We show that for any Hilbert-space dimension, the optimal universal quantum
cloner can be constructed from essentially the same quantum circuit, i.e., we
find a universal design for universal cloners. In the case of infinite
dimensions (which includes continuous variable quantum systems) the universal
cloner reduces to an essentially classical device. More generally, we construct
a universal quantum circuit for distributing qudits in any dimension which acts
covariantly under generalized displacements and momentum kicks. The behavior of
this covariant distributor is controlled by its initial state. We show that
suitable choices for this initial state yield both universal cloners and
optimized cloners for limited alphabets of states whose states are related by
generalized phase-space displacements.Comment: 10 revtex pages, no figure
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