Abstract:
We present a general, analytic recipe to compute the entanglement that is generated between arbitrary, discrete modes of bosonic quantum fields by Bogoliubov transformations. Our setup allows the complete characterization of the quantum correlations in all Gaussian field states. Additionally, it holds for all Bogoliubov transformations. These are commonly applied in quantum optics for the description of squeezing operations, relate the mode decompositions of observers in different regions of curved spacetimes, and describe observers moving along non-stationary trajectories. We focus on a quantum optical example in a cavity quantum electrodynamics setting: an uncharged scalar field within a cavity provides a model for an optical resonator, in which entanglement is created by non-uniform acceleration. We show that the amount of generated entanglement can be magnified by initial single-mode squeezing, for which we provide an explicit formula. Applications to quantum fields in curved spacetimes, such as an expanding universe, are discussed.

Abstract:
We introduce a framework for probing the spacetime structure of vacuum entanglement that exhibits infinite range correlations between the future and the past, as well as spatially separated regions. Our results are non-perturbative and analytical.

Abstract:
We show that particle creation of Bogoliubov modes in a Bose-Einstein condensate due to the accelerated motion of the trap is a genuinely relativistic effect. To this end we show that Bogoliubov modes can be described by a time rescaling of the Minkowski metric. A consequence of this is that Rindler transformations are perceived by the phonons as generalised Rindler transformations where the speed of light is replaced by the speed of sound, enhancing particle creation at small velocities. Since the non-relativistic limit of a Rindler transformation is just a Galilean transformation entailing no length contraction or time dilation, we show that the effect vanishes in the non-relativistic limit.

Abstract:
Unruh-DeWitt detectors interacting locally with a quantum field are systems under consideration for relativistic quantum information processing. In most works, the detectors are assumed to be point-like and, therefore, couple with the same strength to all modes of the field spectrum. We propose the use of a more realistic detector model where the detector has a finite size conveniently tailored by a spatial profile. We design a spatial profile such that the detector, when inertial, naturally couples to a peaked distribution of Minkowski modes. In the uniformly accelerated case, the detector couples to a peaked distribution of Rindler modes. Such distributions are of special interest in the analysis of entanglement in non-inetial frames. We use our detector model to show the noise detected in the Minkowski vacuum and in single particle states is a function of the detector's acceleration.

Abstract:
Understanding the observer-dependent nature of quantum entanglement has been a central question in relativistic quantum information. In this paper we will review key results on relativistic entanglement in flat and curved spacetime and discuss recent work which shows that motion and gravity have observable effects on entanglement between localized systems.

Abstract:
The effect of body weight changes during the breeding season, on the ovulation rate, blood progesterone levels and embryo survival of the crossbreed Mexican ewe was studied. During may to September 2004, 120 crossbreed ewes were selected from a traditional flock in the high mountains (latitude 19 N, 99 W) of Mexico. Divided at random in four groups of 30. Group A with an average body weight of 40.2 1.7 kg was taken to pasture from 9:00 h until 18:00 h daily and received no supplement. Group B with an average weight of 43.8 2.6 kg was taken to pasture as group B and on arrival to their paddocks received 350 g/ewe of commercial concentrate. Group C (42.1 2.4 kg) was range fed only, no supplement was given. Group D (41.2 2 kg) was range fed and 15 days before the introduction of the rams flushing was given, this consisted in 300 g/ewe of a commercial concentrate. This management for all groups was initiated on the first day of May and it was continued until 15 days before the introduction of the rams (July 25). In July 10, ewes of group A showed an average weight of 41.0 2 kg, ewes of group B had a weight average of 51.2 9.1 kg. Ewes of group C and D weighed 45.3 2.3 kg and 44 1.7 kg. To induce body weight changes in groups A and B, in this day, feeding was reversed, group A were range fed and supplemented with concentrated food and ewes of group B were range fed only as previously mentioned. On august 12 weight of groups A and B was 50.3 2 and 42.6 2.5 kg (p = .001) and of groups C and D was 45.4 1.8 and 50.0 2 kg. Groups C and D continued range feeding after the flushing of group D. Body weight in September 8 was 53.7 1.7 kg; 43.5 1.9 kg; 47.8 0.9 and 52.4 2.6 for A, B, C and D groups. Teasing was continued until the end of September. Ovulation rate in ewes displaying oestrus of group A and B was 1.8 .2 and 1.3 .2 and 1.1 .2 and 1.5 .2 for groups C and D, respectively. Difference in between groups AD and BC was significant p = < 0.001. Group A produced 35 lambs. Group B 23, Group C 27 lambs and group D 29. Changes in blood progesterone were non significant, except for group B that showed higher levels. It was concluded that in order to attain higher prolificity in range fed ewes, during the following 3 to 4 weeks after mating, ewes should not suffer of nutritional distress.

Abstract:
We investigate the Hawking effect on entangled fields. By considering a scalar field which is in a two-mode squeezed state from the point of view of freely falling (Kruskal) observers crossing the horizon of a Schwarzschild black hole, we study the degradation of quantum and classical correlations in the state from the perspective of Schwarzschild observers confined outside the horizon. Due to monogamy constraints on the entanglement distribution, we show that the lost bipartite entanglement is recovered as multipartite entanglement among modes inside and outside the horizon. In the limit of a small-mass black hole, no bipartite entanglement is detected outside the horizon, while the genuine multipartite entanglement interlinking the inner and outer regions grows infinitely.

Abstract:
Single quantum system, such as Unruh-DeWitt detector, can be used to determine absolute acceleration by local measurements on a quantum field. To show this, we consider two kinematically indistinguishable scenarios: an inertial observer, Bob, measuring the field of an uniformly accelerated cavity, and his non-inertial twin Rob accelerating and making measurements in a stationary cavity. We find that these scenarios can be distinguished in the non-relativistic regime only by measurements on highly excited massive fields, allowing one to detect non-inertialness of the reference frame.

Abstract:
We address on general quantum-statistical grounds the problem of optimal detection of the Unruh-Hawking effect. We show that the effect signatures are magnified up to potentially observable levels if the scalar field to be probed has high mean energy from an inertial perspective: The Unruh-Hawking effect acts like an amplification channel. We prove that a field in a Fock inertial state, probed via photon counting by a non-inertial detector, realizes the optimal strategy attaining the ultimate sensitivity allowed by quantum mechanics for the observation of the effect. We define the parameter regime in which the effect can be reliably revealed in laboratory experiments, regardless of the specific implementation.

Abstract:
We propose a scheme to investigate whether non-uniform motion degrades entanglement of a relativistic quantum field that is localised both in space and in time. For a Dirichlet scalar field in a cavity in Minkowski space, in small but freely-adjustable acceleration of finite but arbitrarily long duration, degradation of observable magnitude occurs for massless transverse quanta of optical wavelength at Earth gravity acceleration and for kaon mass quanta already at microgravity acceleration. We outline a space-based experiment for observing the effect and its gravitational counterpart.