27,131 research outputs found
Conservation-Dissipation Formalism for Soft Matter Physics: II. Application to Non-isothermal Nematic Liquid Crystals
To most existing non-equilibrium theories, the modeling of non-isothermal
processes was a hard task. Intrinsic difficulties involved the non-equilibrium
temperature, the coexistence of conserved energy and dissipative entropy, etc.
In this paper, by taking the non-isothermal flow of nematic liquid crystals as
a typical example, we illustrated that thermodynamically consistent models in
either vectorial or tensorial forms could be constructed within the framework
of Conservation-Dissipation Formalism (CDF). And the classical isothermal
Ericksen-Leslie model and Qian-Sheng model were shown to be special cases of
our new vectorial and tensorial models in the isothermal, incompressible and
stationary limit. Most importantly, from above examples, it was learnt that
mathematical modeling based on CDF could easily solve the issues relating with
non-isothermal situations in a systematic way. The first and second laws of
thermodynamics were satisfied simultaneously. The non-equilibrium temperature
was defined self-consistently through the partial derivative of entropy
function. Relaxation-type constitutive relations were constructed, which gave
rise to the classical linear constitutive relations, like Newton's law and
Fourier's law, in stationary limits. Therefore, CDF was expected to have a
broad scope of applications in soft matter physics, especially under the
complicated situations, such as non-isothermal, compressible and nanoscale
systems.Comment: 29 page
Passive scheme with a photon-number-resolving detector for monitoring the untrusted source in a plug-and-play quantum-key-distribution system
A passive scheme with a beam splitter and a photon-number-resolving (PNR)
detector is proposed to verify the photon statistics of an untrusted source in
a plug-and-play quantum-key-distribution system by applying a three-intensity
decoy-state protocol. The practical issues due to statistical fluctuation and
detection noise are analyzed. The simulation results show that the scheme can
work efficiently when the total number of optical pulses sent from Alice to Bob
is above 10^8, and the dark count rate of the PNR detector is below 0.5
counts/pulse, which is realizable with current techniques. Furthermore, we
propose a practical realization of the PNR detector with a variable optical
attenuator combined with a threshold detector.Comment: 8 pages, 6 figure
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