Space-times with a stable adiabatic vacuum

1984 ◽  
Vol 16 (5) ◽  
pp. 453-458
Author(s):  
Tevian Dray ◽  
J�rgen Renn
Keyword(s):  
Adiabatic Vacuum

Specific Heat of the Synthetic Rubber Hycar-OR from 15° to 340° K

1943 ◽  
Vol 16 (2) ◽  
pp. 310-317 ◽  
Author(s):  
Norman Bekkedahl ◽  
Russell B. Scott
Keyword(s):  
Heat Equation ◽  
Specific Heat ◽  
Temperature Curve ◽  
Second Order ◽  
Heat Temperature ◽  
A Value ◽  
Synthetic Rubber ◽  
Experimental Values ◽  
Adiabatic Vacuum

Abstract Measurements of specific heat were made on a sample of Hycar-OR synthetic rubber from 15° to 340° K by means of an adiabatic vacuum-type calorimeter. The experimental values of the specific heat between 15° and 22° K were well represented by the Debye specific-heat equation, using a βν value of 80 and, accordingly, the values below 15° K were calculated with this equation. At about 250° K the material has a transition of the second order, the specific heat increasing by about 40 per cent to a value of 1.84 Int. joules · gram−1 · degree−1 just above the transition. From 250° to 340° K the specific heat-temperature curve is nearly linear, and the values can be calculated to within 0.2 per cent from the formula Cp=0.00283T+1.126, in Int. joules · gram−1 · degree−1. At 298.16° K (25° C) the specific heat is 1.971 Int. joules · gram−1 · degree−1 (0.4712 calories · gram−1 · degree−1). The increase in entropy resulting from heating from 0° to 298.16° K was calculated to be 1.743 ± 0.002 Int. joules · gram−1 · degree−1 (0.4167 ± 0.0005 calories · gram−1 · degree−1).

HADAMARD STATES, ADIABATIC VACUA AND THE CONSTRUCTION OF PHYSICAL STATES FOR SCALAR QUANTUM FIELDS ON CURVED SPACETIME

1996 ◽  
Vol 08 (08) ◽  
pp. 1091-1159 ◽  
Author(s):  
WOLFGANG JUNKER
Keyword(s):  
Pseudodifferential Operators ◽  
Cauchy Surface ◽  
Positive Energy ◽  
Hyperbolic Spacetime ◽  
Vacuum States ◽  
Mathematical Review ◽  
Scalar Quantum ◽  
Klein Gordon ◽  
Hadamard States ◽  
Adiabatic Vacuum

Quasifree states of a linear Klein-Gordon quantum field on globally hyperbolic spacetime manifolds are considered. After a short mathematical review techniques from the theory of pseudodifferential operators and wavefront sets on manifolds are used to develop a criterion for a state to be an Hadamard state. It is proven that ground- and KMS-states on certain static spacetimes and adiabatic vacuum states on Robertson-Walker spaces are Hadamard states. A counterexample is given which shows that the idea of instantaneous positive energy states w.r.t. a Cauchy surface does in general not yield physical states. Finally, the problem of constructing Hadamard states on arbitrary curved spacetimes is solved in principle.

scholarly journals Local quasiequivalence and adiabatic vacuum states

1990 ◽  
Vol 134 (1) ◽  
pp. 29-63 ◽  
Author(s):  
Christian Lüders ◽  
John E. Roberts
Keyword(s):  
Vacuum States ◽  
Adiabatic Vacuum

The use of a charcoal adsorption pump in an adiabatic vacuum calorimeter for temperatures between 4·2 and 300° K

Cryogenics ◽  
1967 ◽  
Vol 7 (1-4) ◽  
pp. 297
Author(s):  
G.A. Zaītsev ◽  
V.I. Orcharenko ◽  
V.I. Khotkevich
Keyword(s):  
Charcoal Adsorption ◽  
Adiabatic Vacuum
Sign in / Sign up

Export Citation Format

Share Document