Results 51 to 60 of about 68,867 (287)

Multi-Objective Constructal Design for Square Heat-Generation Body with “Arrow-Shaped” High-Thermal-Conductivity Channel

Energies, 2022
Based on the square heat-generation body (HGB) with “arrow-shaped” high-thermal-conductivity channel (HTCC) model established in the previous literature, we performed multi-objective optimization (MOO) with maximum temperature difference (MTD ...
Hongwei Zhu, Lingen Chen, Yanlin Ge, Shuangshuang Shi, Huijun Feng   +4 more
doaj   +1 more source

Fluctuation, Dissipation and the Arrow of Time [PDF]

, 2011
The recent development of the theory of fluctuation relations has led to new insights into the ever-lasting question of how irreversible behavior emerges from time-reversal symmetric microscopic dynamics.
Bochkov, Callen, Einstein, Messiah, Michele Campisi, Peter Hänggi, Stratonovich   +6 more
core   +6 more sources

Cosmological Time, Entropy and Infinity

Entropy, 2017
Time is a parameter playing a central role in our most fundamental modelling of natural laws. Relativity theory shows that the comparison of times measured by different clocks depends on their relative motion and on the strength of the gravitational ...
Clémentine Hauret, Pierre Magain, Judith Biernaux   +2 more
doaj   +1 more source

Where Was Past Low-Entropy?

Entropy, 2019
Where was the past low-entropy of the early universe located? Contrary to some popular answers, I argue that that the dominant source of low-entropy is the fact that a single degree of freedom, the scale factor, was not at equilibrium.
Carlo Rovelli
doaj   +1 more source

Vacuum structure for expanding geometry [PDF]

, 1999
We consider gravitational wave modes in the FRW metrics in a de Sitter phase and show that the state space splits into many unitarily inequivalent representations of the canonical commutation relations.
Albrecht A, Alfinito E, Alhassid Y, Boyanowski D, Bratteli O, Celeghini E, De Filippo S, E Alfinito, Eboli O, Eboli O, Feshbach H, G Vitiello, Grishchuk L P, Hawking S W, Hawking S W, Hawking S W, Hawking S W, Johansson A E I, Lindblad G, Martellini M, Misner W, Ojima I, Penrose R, Perelomov A M, Prokopec T, R Manka, Sewell G L, Solomon A I, Takahashi Y, Umezawa H, Umezawa H, Vitiello G, Wald R M, Wald R M   +33 more
core   +3 more sources

Arrow of time across five centuries of classical music [PDF]

Physical Review Research, 2020
The concept of time series irreversibility -- the degree by which the statistics of signals are not invariant under time reversal -- naturally appears in non-equilibrium physics in stationary systems which operate away from equilibrium and produce ...
Alfredo González-Espinoza, Gustavo Mart'inez-Mekler, L. Lacasa   +2 more
semanticscholar   +1 more source

Deflation at Turnaround for Oscillatory Cosmology [PDF]

, 2006
It is suggested that dark energy in a brane world can help reconcile an infinitely cyclic cosmology with the second law of thermodynamics. A cyclic cosmology is described, in which dark energy with constant equation of state leads to a turnaround at ...
Baum, Lauris, Frampton, Paul H.
core   +5 more sources

Black-Hole Uncertainty Entails an Intrinsic Time Arrow. a Note on the Hawking-Penrose Controversy [PDF]

, 1999
Any theory that states that the basic laws of physics are time-symmetric must be strictly deterministic. Only determinism enables time reversal of entropy increase. A contradiction therefore arises between two statements of Hawking.
't Hooft, Avshalom C. Elitzur, Dolev, Elitzur, Elitzur, Elitzur, Elitzur, Elitzur, Finkelstein, Ghirardi, Hawking, Hawking, Hawking, Hawking, Hawking, Hawking, Penrose, Penrose, Preskill, Price, Shahar Dolev, Unruh   +21 more
core   +4 more sources

The Decoherent Arrow of Time and the Entanglement Past Hypothesis [PDF]

Foundations of physics
If an asymmetry in time does not arise from the fundamental dynamical laws of physics, it may be found in special boundary conditions. The argument normally goes that since thermodynamic entropy in the past is lower than in the future according to the ...
Jim Al-Khalili, Eddy Keming Chen
semanticscholar   +1 more source

Comment on `Quantum resolution to the arrow of time dilemma' [PDF]

, 2009
Recently, a substantial amount of debate has grown up around a proposed quantum resolution to the `arrow of time dilemma' that is based on the role of classical memory records of entropy-decreasing events.
Jennings, David, Rudolph, Terry
core   +2 more sources