Rotating Unruh-DeWitt Detector in Minkowski Vacuum

Response of a circularly rotating Unrh-DeWitt detector to the Minkowski vacuum is investigated. What the detector observes depends on the surface (three volume) to define it by the Hamiltonian. Detectors in the past literature were defined on a surface of a constant Minkowski time, and this is the reason why rotating detectors investigated so far resister particles. No particle is detected by a detector defined by the Hamiltonian on a surface normal to the detector's orbit, in agreement with the global analysis of vacua. A detector with drift motion superposed on the linear acceleration is also examined, to find the same effect.Comment: 15 pages, 1 figur

Lorentz Transform of Black Body Radiation Temperature

The Lorentz transform of black body radiation has been investigated from the view point of relativistic statistical mechanics. The result shows that the well known expression with the directional temperature can be derived based on the inverse temperature four vector. The directional temperature in the past literature was the result of mathematical manipulation and its physical meaning is not clear. The inverse temperature four vector has, in contrast, clear meaning to understand relativistic thermodynamical processes.Comment: 6 pages, no figur

Three Views of a Secret in Relativistic Thermodynamics

It has been shown three different views in relativistic thermodynamics can be derived from the basic formulation proposed by van Kampen and Israel. The way to decompose energy-momentum into the reversible and irreversible parts is not uniquely determined, and different choices result in different views. The effect of difference in the definition of a finite volume is also considered.Comment: 4 pages, no figure

On Hawking/Unruh Process: Where does the Radiation Come from?

The energy source of the radiation in Unruh/Hawking process is investigated with emphasis on the particle number definition based on conservation laws. It has been shown that the particle radiation is not the result of pair creation by the gravitational force, but the result of difference in the conservation laws to define the particle number. The origin of the radiated energy in the distant future corresponds to the zero point oscillations with infinitely large wave numbers. This result implies the need of reconsideration on the scenario of black hole evaporation.Comment: 11 pages, 0 figures; fixed typo and minor errors, changed page styl

Minkowski momentum of an MHD wave

The momentum of an MHD wave has been examined from the view point of the electromagnetic momentum expression derived by Minkowski. Basic calculations show that the Minkowski momentum is the sum of electromagnetic momentum and the momentum of the medium, as proposed in some of the past literature. The result has been explicitly confirmed by an example of an MHD wave, whose dynamics can be easily and precisely calculated from basic equations. The example of MHD wave also demonstrates the possiblility to construct a symmetric energy-momentum tensor based on the Minkowski momentum.Comment: 8 pages, not figur

Factor Two Discrepancy of Hawking Radiation Temperature

The possibility of an alternative way to formulate the Hawking radiation in a static Schwarzschild spacetime has been explored. To calculate the Hawking radiation, there can be two possible choices of the spacetime wedge pairs in the Krucal-Szekeres coordinates. One is the wedge pair consists of exterior spacetime of a black hole and the exterior spacetime of a white hole, and the other is that of exterior and interior spacetimes of one black hole. The radiation from the former is the Hawking's original one. Though the the latter has been often regarded as the same phenomena as the former, the result here suggests it is not; its radiation has a temperature twice as high as the Hawking temperature.Comment: 10 pages, 1 figure, v2: abstract, introduction, discussions section revise

Second Order Gauge Invariant Perturbation Theory -- Perturbative curvatures in the two-parameter case --

Based on the gauge invariant variables proposed in our previous paper [K. Nakamura, Prog. Theor. Phys. vol.110 (2003), 723.], some formulae of the perturbative curvatures of each order are derived. We follow the general framework of the second order gauge invariant perturbation theory on arbitrary background spacetime to derive these formulae. These perturbative curvatures do have the same form as the definitions of gauge invariant variables for arbitrary perturbative fields which are previously proposed. As a result, we explicitly see that any perturbative Einstein equations are given in terms of gauge invarinat form. We briefly discuss physical situations to which this framework should be applied.Comment: 31 pages, 1 figure, PTPTEX (ptptex.cls ver 0.9);Some typos in the published version are correcte

Cylindrical Domain Walls and Gravitational Waves -- Einstein Rosen wave emission from momentarily static initial configuration --

A self-gravitating cylindrical domain wall is considered as an example of non-spherical wall to clarify the interaction between a domain wall and gravitational waves. We consider the time evolution from a momentarily static initial configuration within an infinitesimal time interval using the metric junction formalism. We found that the wall with a large initial radius radiates large amplitude of the gravitational waves and undergoes its large back reaction.Comment: 3 pages, latex requires mprocl.sty, no figures. To appear in the proceedings of the Eighth Marcel Grossmann Conference on General Relativity (Jerusalem, Israel, June 1997

Gauge-invariant variables in general-relativistic perturbations: globalization and zero-mode problem

An outline of a proof of the local decomposition of linear metric perturbations into gauge-invariant and gauge-variant parts on an arbitrary background spacetime is briefly explained. We explicitly construct the gauge-invariant and gauge-variant parts of the linear metric perturbations based on some assumptions. We also point out the zero-mode problem is an essential problem to globalize of this decomposition of linear metric perturbations. The resolution of this zero-mode problem implies the possibility of the development of the higher-order gauge-invariant perturbation theory on an arbitrary background spacetime in a global sense.Comment: (v1) 16 pages, no figure; (v2) 9 pages, no figure. Compactified for "2012 Awards for Essays on Gravitation" promoted by Gravity Research Foundation. References are deleted. no ingredients is changed. This version received Honorable Mention for 201

IsoDAR@KamLAND:A Conceptual Design Report for the Conventional Facilities

This document describes requirements for the caverns to house the cyclotron, beam transport line, and target systems; issues associated with transport and assembly of components on the site; electrical power, cooling and ventilation; as well as issues associated with radiation protection of the environment and staff of KamLAND who will be interfacing with IsoDAR during its operational phases. Specifics of IsoDAR operations at the KamLAND site are not addressed. Recent developments in planning for deployment of IsoDAR include the identification of a potential new site for the experiment, where the target can be placed directly on the equatorial plane of the KamLAND detector, and also, an upgrade of the detector resolution to 3\%/$\sqrt{E(MeV)}$. The option of the new site might allow, depending on the results of shielding and background evaluations in KamLAND, for an increase in event rate by about a factor of 1.6 owing to increased solid angle for the detector, improving the physics reach for a same period of the experiment. Alternatively, it raises the option of reducing technical risk and cost by reducing beam intensity to maintain the originally planned event rates. This new siting option is described, and aspects the physics reach of the sterile neutrino search are updated to reflect this second option, as well as the higher resolution of the experiment. A full update of the physics capability given the new site and resolution is beyond the scope of this CDR and will be published later