arXiv subjects
Publications and source records attributed to A. Z. Capri.
We adapt a calculation due to Massacand and Schmid to the coordinate independent definition of time and vacuum given by Capri and Roy in order to compute the trace anomaly for a massless scalar field in a curved spacetime in 1+1 dimensions. The computation which requires only a simple regulator and normal ordering yields the well-known result $\frac{R}{24π}$ in a straightforward manner.
In this paper we calculate the particle creation as seen by a stationary observer in 3+1 de Sitter space. This particle creation is calculated using an observer dependent geometrically based definition of time which is used to quantize a field on two different spacelike surfaces. The Bogolubov transformation relating these two quantizations is then calculated and the resulting particle creation is shown to be finite.
In this paper we calculate the massive particle creation as seen by a stationary observer in a $1+1$ dimensional spacetime compact in space. The Bogolubov transformation relating the annihilation and creation operators between two spacelike surfaces is calculated. The particle creation, as observed by a stationary observer who moves from the first spacelike surface to the second is then calculated, and shown to be finite, as is expected for a spacetime with finite spatial volume.
In this paper we calculate the particle creation as seen by a stationary observer in an anisotropic universe. By using an observer and geometry dependent time to quantise a massive scalar field we show that a discrete energy spectrum shift occurs. The length scale associated with the geometry provides the energy scale by which the spectrum is shifted. The $β(p,q)$ coefficient for the Bogolubov transformation calculated is proportional to a series of delta functions whose argument contains $p$ and $q$ and half multiples of the root of the curvature.
We show explicitly that there is particle creation in a static spacetime. This is done by studying the field in a coordinate system based on a physical principle which has recently been proposed. There the field is quantized by decomposing it into positive and negative frequency modes on a particular spacelike surface. This decomposition depends explicitly on the surface where the decomposition is performed, so that an observer who travels from one surface to another will observe particle production due to the different vacuum state.
We consider the Krein realization of the Hilbert space for a massless scalar field in 1+1 dimensions. We find convergence criteria and the completion of the space of test functions ${\cal S}$ with the topology induced by the Krein scalar product. Finally, we show that the interpretation for the Fourier components as probability amplitudes for the momentum operator is lost in this case.