Localised projective measurement of a relativistic quantum field in non-inertial frames

We propose a scheme to study the effect of motion on measurements of a quantum field carried out by a finite-size detector. We introduce a model of projective detection of a localised field mode in an arbitrary reference frame. We apply it to extract vacuum entanglement by a pair of counter-accelerating detectors and to estimate the Unruh temperature of a single accelerated detector. The introduced method allows us to directly relate the observed effects with the instantaneous proper acceleration of the detector.Comment: 5 pages, 2 figures. v2 Significant increase in the detail level regarding the motivation of the detector mode

Nonlinear brain dynamics and many-body field dynamics

We report measurements of the brain activity of subjects engaged in behavioral exchanges with their environments. We observe brain states which are characterized by coordinated oscillation of populations of neurons that are changing rapidly with the evolution of the meaningful relationship between the subject and its environment, established and maintained by active perception. Sequential spatial patterns of neural activity with high information content found in sensory cortices of trained animals between onsets of conditioned stimuli and conditioned responses resemble cinematographic frames. They are not readily amenable to description either with classical integrodifferential equations or with the matrix algebras of neural networks. Their modeling is provided by field theory from condensed matter physics.Comment: 8 pages, Invited talk presented at Fr\"ohlich Centenary International Symposium "Coherence and Electromagnetic Fields in Biological Systems", July 1-4, 2005, Prague, Czech Republi

Interplay of causticity and vorticality within the complex quantum Hamilton-Jacobi formalism

Interference dynamics is analyzed in the light of the complex quantum Hamilton-Jacobi formalism, using as a working model the collision of two Gaussian wave packets. Though simple, this model nicely shows that interference in quantum scattering processes gives rise to rich dynamics and trajectory topologies in the complex plane, both ruled by two types of singularities: caustics and vortices, where the former are associated with the regime of free wave-packet propagation, and the latter with the collision (interference) process. Furthermore, an unambiguous picture connecting the complex and real frameworks is also provided and discussed.Comment: 12 pages, 3 figure

Spin decoherence by spacetime curvature

A decoherence mechanism caused by spacetime curvature is discussed. The spin state of a particle is shown to decohere if only the particle moves in a curved spacetime. In particular, when a particle is near the event horizon of a black hole, an extremely rapid spin decoherence occurs for an observer who is static in a Killing time, however slow the particle's motion is.Comment: 13 pages, 2 figure