Friction and inertia for a mirror in a thermal field

The force experienced by a mirror moving in vacuum vanishes in the case of uniform velocity or uniform acceleration, as a consequence of spatial symmetries of vacuum. These symmetries do not subsist in a thermal field. We give a general expression of the corresponding viscosity coefficient valid at any temperature and for any reflectivity function. We show that the computed motional force also contains a non vanishing inertial term. The associated mass correction goes to zero in the limiting cases of perfect reflection or of zero temperature.Comment: 5 page

Quantum Fluctuations of Mass for a Mirror in Vacuum

A mirror in vacuum is coupled to fluctuating quantum fields. As a result, its energy-momentum and mass fluctuate. We compute the correlation spectra of force and mass fluctuations for a mirror at rest in vacuum (of a scalar field in a two-dimensional space-time). The obtained expressions agree with a mass correction equal to a vacuum energy stored by the mirror. We introduce a Lagrangian model which consistently describes a scalar field coupled to a scatterer, with inertial mass being a quantum variable.Comment: 6 page

Observable Dirac Electron in Accelerated Frames

We present a new quantum algebraic description of an electron localized in space-time. Positions in space and time, mass and Clifford generators are defined as quantum operators. Commutation relations and relativistic shifts under frame transformations are determined within a unique algebraic framework. Redshifts, i.e. shifts under transformations to uniformly accelerated frames, are evaluated and found to differ from the expressions of classical relativity.Comment: 7 pages, revised versio

Causality, stability and passivity for a mirror in vacuum

The mean force exerted upon a perfect mirror moving in vacuum in a two dimensional spacetime has the same expression as the radiation reaction force computed in classical electron theory. It follows that unacceptable runaway solutions are predicted. We show that this instability problem does not appear when partially transmitting mirrors are studied. The mechanical impedance describing the mirror coupled to vacuum radiation pressure is computed explicitly; recoil is neglected. It is found to be a passive function, so that stability is ensured. This is connected to the fact that no energy can be extracted from the vacuum state.Comment: 5 pages, corrected typo in formula

The Relation Between KMS-states for Different Temperatures

Given a thermal field theory for some temperature $\beta^{-1}$, we construct the theory at an arbitrary temperature $1 / \beta'$. Our work is based on a construction invented by Buchholz and Junglas, which we adapt to thermal field theories. In a first step we construct states which closely resemble KMS states for the new temperature in a local region \O_\circ \subset \rr^4, but coincide with the given KMS state in the space-like complement of a slightly larger region \hat{\O}. By a weak*-compactness argument there always exists a convergent subnet of states as the size of \O_\circ and \hat{\O} tends towards \rr^4. Whether or not such a limit state is a global KMS state for the new temperature, depends on the surface energy contained in the layer in between the boundaries of \O_\circ and \hat{\O}. We show that this surface energy can be controlled by a generalized cluster condition.Comment: latex, 24 page

The Reeh-Schlieder property for ground states

Recently it has been shown that the Reeh-Schlieder property w.r.t. thermal equilibrium states is a direct consequence of locality, additivity and the relativistic KMS condition. Here we extend this result to ground states.Comment: plain tex, 11 pages, An unnecessary strong assumption has been replaced by a more adequate one in Definition 2.

Decay of Spatial Correlations in Thermal States

We study the cluster properties of thermal equilibrium states in theories with a maximal propagation velocity (such as relativistic QFT). Our analysis, carried out in the setting of algebraic quantum field theory, shows that there is a tight relation between spectral properties of the generator of time translations and the decay of spatial correlations in thermal equilibrium states, in complete analogy to the well understood case of the vacuum state.Comment: plain tex, 13 pages. To appear in Ann. Inst. H. Poinc. (Phys. Theor.

Gravity tests in the solar system and the Pioneer anomaly

We build up a new phenomenological framework associated with a minimal generalization of Einsteinian gravitation theory. When linearity, stationarity and isotropy are assumed, tests in the solar system are characterized by two potentials which generalize respectively the Newton potential and the parameter $\gamma$ of parametrized post-Newtonian formalism. The new framework seems to have the capability to account for the Pioneer anomaly besides other gravity tests.Comment: 5 pages. Accepted version, to appear in Modern Physics Letters