748 research outputs found
Singular limit of an integrodifferential system related to the entropy balance
A thermodynamic model describing phase transitions with thermal memory, in
terms of an entropy equation and a momentum balance for the microforces, is
adressed. Convergence results and error estimates are proved for the related
integrodifferential system of PDE as the sequence of memory kernels converges
to a multiple of a Dirac delta, in a suitable sense.Comment: Key words: entropy equation, thermal memory, phase field model,
nonlinear partial differential equations, asymptotics on the memory ter
Classical capacity of Gaussian thermal memory channels
The classical capacity of phase-invariant Gaussian channels has been recently
determined under the assumption that such channels are memoryless. In this work
we generalize this result by deriving the classical capacity of a model of
quantum memory channel, in which the output states depend on the previous input
states. In particular we extend the analysis of [C. Lupo, et al., PRL and PRA
(2010)] from quantum limited channels to thermal attenuators and thermal
amplifiers. Our result applies in many situations in which the physical
communication channel is affected by nonzero memory and by thermal noise.Comment: 14 pages, 8 figure
Landauer's erasure principle in a squeezed thermal memory
Landauer's erasure principle states that the irreversible erasure of a
one-bit memory, embedded in a thermal environment, is accompanied with a work
input of at least . Fundamental to that principle is the
assumption that the physical states representing the two possible logical
states are close to thermal equilibrium. Here, we propose and theoretically
analyze a minimalist mechanical model of a one-bit memory operating with
squeezed thermal states. It is shown that the Landauer energy bound is
exponentially lowered with increasing squeezing factor. Squeezed thermal
states, which may naturally arise in digital electronic circuits operating in a
pulse-driven fashion, thus can be exploited to reduce the fundamental energy
costs of an erasure operation.Comment: 5 pages, 3 figure
Identification of a convolution kernel in a control problem for the heat equation with a boundary memory term
We consider the evolution of the temperature in a material with thermal
memory characterized by a time-dependent convolution kernel . The material
occupies a bounded region with a feedback device controlling the
external temperature located on the boundary . Assuming both and
unknown, we formulate an inverse control problem for an integrodifferential
equation with a nonlinear and nonlocal boundary condition. Existence and
uniqueness results of a solution to the inverse problem are proved
Thermal bistability through coupled photonic resonances
We present a scheme for achieving thermal bistability based on the selective
coupling of three optical resonances. This approach requires one of the
resonant frequencies to be temperature dependent, which can occur in materials
exhibiting strong thermo-optic effects. For illustration, we explore thermal
bistability in two different passive systems, involving either a periodic array
of Si ring resonators or parallel GaAs thin films separated by vacuum and
exchanging heat in the near field. Such a scheme could prove useful for thermal
memory devices operating with transition times hundreds of
milliseconds
Thermal memory: a storage of phononic information
Memory is an indispensable element for computer besides logic gates. In this
Letter we report a model of thermal memory. We demonstrate via numerical
simulation that thermal (phononic) information stored in the memory can be
retained for a long time without being lost and more importantly can be read
out without being destroyed. The possibility of experimental realization is
also discussed.Comment: 5 pages, 3 figures
- …