3,577 research outputs found
Thermodynamics of relativistic quantum fields confined in cavities
We investigate the quantum thermodynamical properties of localised
relativistic quantum fields, and how they can be used as quantum thermal
machines. We study the efficiency and power of energy transfer between the
classical gravitational degrees of freedom, such as the energy input due to the
motion of boundaries or an impinging gravitational wave, and the excitations of
a confined quantum field. We find that the efficiency of energy transfer
depends dramatically on the input initial state of the system. Furthermore, we
investigate the ability of the system to extract energy from a gravitational
wave and store it in a battery. This process is inefficient in optical cavities
but is significantly enhanced when employing trapped Bose Einstein condensates.
We also employ standard fluctuation results to obtain the work probability
distribution, which allows us to understand how the efficiency is related to
the dissipation of work. Finally, we apply our techniques to a setup where an
impinging gravitational wave excites the phononic modes of a Bose Einstein
condensate. We find that, in this case, the percentage of energy transferred to
the phonons approaches unity after a suitable amount of time. These results
give a quantitative insight into the thermodynamic behaviour of relativistic
quantum fields confined in cavities.Comment: 35 pages, 3 figures. Manuscript substantially updated. I. Fuentes
also published as I. Fuentes-Guridi and I. Fuentes-Schulle
Quantum metrology for relativistic quantum fields
In quantum metrology quantum properties such as squeezing and entanglement
are exploited in the design of a new generation of clocks, sensors and other
measurement devices that can outperform their classical counterparts.
Applications of great technological relevance lie in the precise measurement of
parameters which play a central role in relativity, such as proper
accelerations, relative distances, time and gravitational field strengths. In
this paper we generalise recently introduced techniques to estimate physical
quantities within quantum field theory in flat and curved space-time. We
consider a bosonic quantum field that undergoes a generic transformation, which
encodes the parameter to be estimated. We present analytical formulas for
optimal precision bounds on the estimation of small parameters in terms of
Bogoliubov coefficients for single mode and two-mode Gaussian channels.Comment: Ivette Fuentes previously published as I. Fuentes-Guridi and I.
Fuentes-Schulle
Time evolution techniques for detectors in relativistic quantum information
The techniques employed to solve the interaction of a detector and a quantum
field typically require perturbation methods. We introduce mathematical
techniques to solve the time evolution of an arbitrary number of detectors
interacting with a quantum field. Our techniques apply to harmonic oscillator
detectors and can be generalized to treat detectors modeled by quantum fields.
Since the interaction Hamiltonian we introduce is quadratic in creation and
annihilation operators, we are able to draw from continuous variable techniques
commonly employed in quantum optics.Comment: 13 pages, 1 figure, updated to published version . I. Fuentes
previously published as I. Fuentes-Guridi and I. Fuentes-Schulle
Thermal noise in BEC-phononic gravitational wave detectors
Quasiparticles in a Bose-Einstein condensate are sensitive to space-time
distortions. Gravitational waves can induce transformations on the state of
phonons that can be observed through quantum state discrimination techniques.
We show that this method is highly robust to thermal noise and depletion. We
derive a bound on the strain sensitivity that shows that the detection of waves
in the kHz regime is not significantly affected by temperature in a wide range
of parameters that are well within current experimental reach.Comment: 6 pages, 4 figures. v2: 9 pages, 5 figures. Appendix added. Published
versio
Multi-Resolution Texture Coding for Multi-Resolution 3D Meshes
We present an innovative system to encode and transmit textured multi-resolution 3D meshes in a progressive way, with no need to send several texture images, one for each mesh LOD (Level Of Detail). All texture LODs are created from the finest one (associated to the finest mesh), but can be re- constructed progressively from the coarsest thanks to refinement images calculated in the encoding process, and transmitted only if needed. This allows us to adjust the LOD/quality of both 3D mesh and texture according to the rendering power of the device that will display them, and to the network capacity. Additionally, we achieve big savings in data transmission by avoiding altogether texture coordinates, which are generated automatically thanks to an unwrapping system agreed upon by both encoder and decoder
Quantum gates and multipartite entanglement resonances realized by non-uniform cavity motion
We demonstrate the presence of genuine multipartite entanglement between the
modes of quantum fields in non-uniformly moving cavities. The transformations
generated by the cavity motion can be considered as multipartite quantum gates.
We present two setups for which multi-mode entanglement can be generated for
bosons and fermions. As a highlight we show that the bosonic genuine
multipartite correlations can be resonantly enhanced. Our results provide
fundamental insights into the structure of Bogoliubov transformations and
suggest strong links between quantum information, quantum fields in curved
spacetimes and gravitational analogs by way of the equivalence principle.Comment: v2: extended to 9 pages, 2 figures, appendix with explicit witness
inequalities added; to appear in Phys. Rev. D; Ivette Fuentes previously
published as Ivette Fuentes-Guridi and Ivette Fuentes-Schulle
Mode-mixing quantum gates and entanglement without particle creation in periodically accelerated cavities
We show that mode-mixing quantum gates can be produced by non-uniform
relativistic acceleration. Periodic motion in cavities exhibits a series of
resonant conditions producing entangling quantum gates between different
frequency modes. The resonant condition associated with particle creation is
the main feature of the dynamical Casimir effect which has been recently
demonstrated in superconducting circuits. We show that a second resonance,
which has attracted less attention since it implies negligible particle
production, produces a beam splitting quantum gate leading to a resonant
enhancement of entanglement which can be used as the first evidence of
acceleration effects in mechanical oscillators. We propose a desktop experiment
where the frequencies associated with this second resonance can be produced
mechanically.Comment: Ivette Fuentes previously published as Ivette Fuentes-Guridi and
Ivette Fuentes-Schuller. v2: Quantitative analysis of entanglement production
given in subsec II
Particle and anti-particle bosonic entanglement in non-inertial frames
We analyse the entanglement tradeoff between particle and anti-particle modes
of a charged bosonic field between inertial and uniformly accelerated
observers. In contrast with previous results for fermionic fields, we find that
the entanglement redistribution between particle and antiparticle modes does
not prevent the entanglement from vanishing in the infinite acceleration limit.Comment: Ivette Fuentes previously published as Ivette Fuentes-Guridi and
Ivette Fuentes-Schulle
- âŚ