2,157 research outputs found
Fluctuation theorem for black-body radiation
The fluctuation theorem is verified for black-body radiation, provided the
bunching of photons is taken into account appropriately.Comment: 4 pages, 3 figure
Stochastic thermodynamics for kinetic equations
Stochastic thermodynamics is formulated for variables that are odd under time
reversal. The invariance under spatial rotation of the collision rates due to
the isotropy of the heat bath is shown to be a crucial ingredient. An
alternative detailed fluctuation theorem is derived, expressed solely in terms
of forward statistics. It is illustrated for a linear kinetic equation with
kangaroo rates
Stochastic energetics of a Brownian motor and refrigerator driven by non-uniform temperature
The energetics of a Brownian heat engine and heat pump driven by position
dependent temperature, known as the B\"uttiker-Landauer heat engine and heat
pump, is investigated by numerical simulations of the inertial Langevin
equation. We identify parameter values for optimal performance of the heat
engine and heat pump. Our results qualitatively differ from approaches based on
the overdamped model. The behavior of the heat engine and heat pump, in the
linear response regime is examined under finite time conditions and we find
that the efficiency is lower than that of an endoreversible engine working
under the same condition. Finally, we investigate the role of different
potential and temperature profiles to enhance the efficiency of the system. Our
simulations show that optimizing the potential and temperature profile leads
only to a marginal enhancement of the system performance due to the large
entropy production via the Brownian particle's kinetic energy.Comment: 14 pages, 15 figures (latest version with modified figures and text
First Measurement of the Hubble Constant from a Dark Standard Siren using the Dark Energy Survey Galaxies and the LIGO/Virgo Binary-Black-hole Merger GW170814
We present a multi-messenger measurement of the Hubble constant H 0 using the binary-black-hole merger GW170814 as a standard siren, combined with a photometric redshift catalog from the Dark Energy Survey (DES). The luminosity distance is obtained from the gravitational wave signal detected by the Laser Interferometer Gravitational-Wave Observatory (LIGO)/Virgo Collaboration (LVC) on 2017 August 14, and the redshift information is provided by the DES Year 3 data. Black hole mergers such as GW170814 are expected to lack bright electromagnetic emission to uniquely identify their host galaxies and build an object-by-object Hubble diagram. However, they are suitable for a statistical measurement, provided that a galaxy catalog of adequate depth and redshift completion is available. Here we present the first Hubble parameter measurement using a black hole merger. Our analysis results in , which is consistent with both SN Ia and cosmic microwave background measurements of the Hubble constant. The quoted 68% credible region comprises 60% of the uniform prior range [20, 140] km s-1 Mpc-1, and it depends on the assumed prior range. If we take a broader prior of [10, 220] km s-1 Mpc-1, we find (57% of the prior range). Although a weak constraint on the Hubble constant from a single event is expected using the dark siren method, a multifold increase in the LVC event rate is anticipated in the coming years and combinations of many sirens will lead to improved constraints on H 0
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