4,891 research outputs found
Quantum Communications with Compressed Decoherence Using Bright Squeezed Light
We propose a scheme for long-distance distribution of quantum entanglement in
which the entanglement between qubits at intermediate stations of the channel
is established by using bright light pulses in squeezed states coupled to the
qubits in cavities with a weak dispersive interaction. The fidelity of the
entanglement between qubits at the neighbor stations (10 km apart from each
other) obtained by postselection through the balanced homodyne detection of 7
dB squeezed pulses can reach F=0.99 without using entanglement purification, at
same time, the probability of successful generation of entanglement is 0.34.Comment: 4 pages, 2 figure
Self-Similar Blowup Solutions to the 2-Component Camassa-Holm Equations
In this article, we study the self-similar solutions of the 2-component
Camassa-Holm equations% \begin{equation} \left\{ \begin{array} [c]{c}%
\rho_{t}+u\rho_{x}+\rho u_{x}=0
m_{t}+2u_{x}m+um_{x}+\sigma\rho\rho_{x}=0 \end{array} \right. \end{equation}
with \begin{equation} m=u-\alpha^{2}u_{xx}. \end{equation} By the separation
method, we can obtain a class of blowup or global solutions for or
. In particular, for the integrable system with , we have the
global solutions:% \begin{equation} \left\{ \begin{array} [c]{c}%
\rho(t,x)=\left\{ \begin{array} [c]{c}% \frac{f\left( \eta\right)
}{a(3t)^{1/3}},\text{ for }\eta^{2}<\frac {\alpha^{2}}{\xi}
0,\text{ for }\eta^{2}\geq\frac{\alpha^{2}}{\xi}% \end{array} \right.
,u(t,x)=\frac{\overset{\cdot}{a}(3t)}{a(3t)}x
\overset{\cdot\cdot}{a}(s)-\frac{\xi}{3a(s)^{1/3}}=0,\text{ }a(0)=a_{0}%
>0,\text{ }\overset{\cdot}{a}(0)=a_{1}
f(\eta)=\xi\sqrt{-\frac{1}{\xi}\eta^{2}+\left( \frac{\alpha}{\xi}\right)
^{2}}% \end{array} \right. \end{equation}
where with and are
arbitrary constants.\newline Our analytical solutions could provide concrete
examples for testing the validation and stabilities of numerical methods for
the systems.Comment: 5 more figures can be found in the corresponding journal paper (J.
Math. Phys. 51, 093524 (2010) ). Key Words: 2-Component Camassa-Holm
Equations, Shallow Water System, Analytical Solutions, Blowup, Global,
Self-Similar, Separation Method, Construction of Solutions, Moving Boundar
Changes in Polarization Position Angle across the Eclipse in the Double Pulsar System
We investigate the changes in polarization position angle in radiation from
pulsar A around the eclipse in the Double Pulsar system PSR J0737-3039A/B at
the 20 cm and 50 cm wavelengths using the Parkes 64-m telescope. The changes
are ~2\sigma\ during and shortly after the eclipse at 20 cm but less
significant at 50 cm. We show that the changes in position angle during the
eclipse can be modelled by differential synchrotron absorption in the eclipse
regions. Position angle changes after the eclipse are interpreted as Faraday
rotation in the magnetotail of pulsar B. Implied charge densities are
consistent with the Goldreich-Julian density, suggesting that the particle
energies in the magnetotail are mildly relativistic.Comment: Accepted for publication in The Astrophysical Journal Letter
Two-mode heterodyne phase detection
We present an experimental scheme that achieves ideal phase detection on a
two-mode field. The two modes and are the signal and image band modes
of an heterodyne detector, with the field approaching an eigenstate of the
photocurrent . The field is obtained by means of a
high-gain phase-insensitive amplifier followed by a high-transmissivity
beam-splitter with a strong local oscillator at the frequency of one of the two
modes.Comment: 3 pages, 1 figur
Continuous variable cloning via network of parametric gates
We propose an experimental scheme for the cloning machine of continuous
quantum variables through a network of parametric amplifiers working as
input-output four-port gates.Comment: 4 pages, 2 figures. To appear on Phys. Rev. Let
Minimum output entropy of bosonic channels: a conjecture
The von Neumann entropy at the output of a bosonic channel with thermal noise
is analyzed. Coherent-state inputs are conjectured to minimize this output
entropy. Physical and mathematical evidence in support of the conjecture is
provided. A stronger conjecture--that output states resulting from
coherent-state inputs majorize the output states from other inputs--is also
discussed.Comment: 15 pages, 12 figure
Polariton-assisted Singlet Fission in Acene Aggregates
Singlet fission is an important candidate to increase energy conversion
efficiency in organic photovoltaics by providing a pathway to increase the
quantum yield of excitons per photon absorbed in select materials. We
investigate the dependence of exciton quantum yield for acenes in the strong
light-matter interaction (polariton) regime, where the materials are embedded
in optical microcavities. Starting from an open-quantum-systems approach, we
build a kinetic model for time-evolution of species of interest in the presence
of quenchers and show that polaritons can decrease or increase exciton quantum
yields compared to the cavity-free case. In particular, we find that hexacene,
a typically poor singlet-fission candidate, can feature a higher yield than
cavity-free pentacene when assisted by polaritonic effects. Similarly, we show
that pentacene yield can be increased when assisted by polariton states.
Finally, we address how various relaxation processes between bright and dark
states in lossy microcavities affect polariton photochemistry. Our results also
provide insights on how to choose microcavities to enhance similarly related
chemical processes.Comment: 12 pages, 4 figure
Isotropic phase squeezing and the arrow of time
We prove that isotropic squeezing of the phase is equivalent to reversing the
arrow of time.Comment: 8 pages. 2 eps figures. elsart styl
- âŠ