Large scale EPR correlations and cosmic gravitational waves

We study how quantum correlations survive at large scales in spite of their exposition to stochastic backgrounds of gravitational waves. We consider Einstein-Podolski-Rosen (EPR) correlations built up on the polarizations of photon pairs and evaluate how they are affected by the cosmic gravitational wave background (CGWB). We evaluate the quantum decoherence of the EPR correlations in terms of a reduction of the violation of the Bell inequality as written by Clauser, Horne, Shimony and Holt (CHSH). We show that this decoherence remains small and that EPR correlations can in principle survive up to the largest cosmic scales.Comment: 5 figure

Quantum limits in interferometric measurements

Quantum noise limits the sensitivity of interferometric measurements. It is generally admitted that it leads to an ultimate sensitivity, the ``standard quantum limit''. Using a semi-classical analysis of quantum noise, we show that a judicious use of squeezed states allows one in principle to push the sensitivity beyond this limit. This general method could be applied to large scale interferometers designed for gravitational wave detection.Comment: 4 page

Thermal Casimir force between nanostructured surfaces

We present detailed calculations for the Casimir force between a plane and a nanostructured surface at finite temperature in the framework of the scattering theory. We then study numerically the effect of finite temperature as a function of the grating parameters and the separation distance. We also infer non-trivial geometrical effects on the Casimir interaction via a comparison with the proximity force approximation. Finally, we compare our calculations with data from experiments performed with nanostructured surfaces

Reply to ``Comment on ``Lateral Casimir Force beyond the Proximity Force Approximation'' ''

We reply to the comment arXiv:quant-ph/0702060 on our letter arXiv:quant-ph/0603120 [Phys. Rev. Lett. 96, 100402 (2006)]Comment: 1 pag

Testing gravity law in the solar system

The predictions of General relativity (GR) are in good agreement with observations in the solar system. Nevertheless, unexpected anomalies appeared during the last decades, along with the increasing precision of measurements. Those anomalies are present in spacecraft tracking data (Pioneer and flyby anomalies) as well as ephemerides. In addition, the whole theory is challenged at galactic and cosmic scales with the dark matter and dark energy issues. Finally, the unification in the framework of quantum field theories remains an open question, whose solution will certainly lead to modifications of the theory, even at large distances. As long as those "dark sides" of the universe have no universally accepted interpretation nor are they observed through other means than the gravitational anomalies they have been designed to cure, these anomalies may as well be interpreted as deviations from GR. In this context, there is a strong motivation for improved and more systematic tests of GR inside the solar system, with the aim to bridge the gap between gravity experiments in the solar system and observations at much larger scales. We review a family of metric extensions of GR which preserve the equivalence principle but modify the coupling between energy and curvature and provide a phenomenological framework which generalizes the PPN framework and "fifth force" extensions of GR. We briefly discuss some possible observational consequences in connection with highly accurate ephemerides.Comment: Proceedings of Journ\'ees 2010 "Syst\`emes de r\'ef\'erence spatio-temporels", New challenges for reference systems and numerical standards in astronom

Творчество Уильяма Гибсона в контексте трансгуманизма

Анализируется новаторство Гибсона в научной фантастике. Рассматривается концепт окружающей среды в сеттингах Гибсона, сравнивается с идеями техногайянизма, указываются возникшие между ними противоречия и несоответствия. Исследуется достороверность футурологических прогнозов Гибсона. Перечисляются основные достижения науки на данном поприще и сравниваются с литературными предсказаниями Гибсона. Изучается характер героев произведений Гибсона. Приводится характеристика киберпространства – термина, впервые введённого Гибсоном в оборот. Романы Гибсона сравниваются с идеями научного иммортализма, указываются возникшие между ними противоречия и несоответствия. Подробнее рассматривается литературный трансгуманизм и его функционирование в литературной среде. Выделяются разновидности трансгуманистического искусства. Проводятся сравнительные параллели между некоторыми художественными приёмами научной фантастики и киберпанка. Исследуется взаимосвязь трансгуманизма и киберпанка. В итоге, определяется степень взаимосвязи между его произведениями в жанре киберпанк и идеями трансгуманизма.Аналізується новаторство Гібсона в науковій фантастиці. Розглядається концепт довкілля в сеттінгах Гібсона, порівнюється з ідеями техногайянізма, вказуються виниклі між ними протиріччя і невідповідності. Досліджується достороверность футурологічних прогнозів Гібсона. Перераховуються основні досягнення науки на даному терені і порівнюються з літературними передбаченнями Гібсона. Вивчається характер героїв творів Гібсона. Приводиться характеристика кіберпростору – терміну, вперше введеного Гібсоном в зворот. Романи Гібсона порівнюються з ідеями наукового імморталізма, вказуються виниклі між ними протиріччя і невідповідності. Детальніше розглядається літературний трансгуманізм і його функціонування в літературному середовищі. Виділяються різновиди трансгуманістічеського мистецтва. Проводяться порівняльні паралелі між деякими художніми прийомами наукової фантастики і киберпанка. Досліджується взаємозв'язок трансгуманізма і киберпанка. У результаті, визначається міра взаємозв'язку між його творами в жанрі киберпанк і ідеями трансгуманізма.William Gibson’s works in the context of transhumanism doctrine, technogaianism and scientific immortalism. The innovations of Gibson’s literature are analyzed. The environmental concept in Gibson’s settings is examined, compared to the ideas of technogaianism; the resulting contradictions and disparities arising between them are specified. The faithfulness of Gibson’s futurological forecast is probed. Basic achievements of science are compared to the futurological estimates of Gibson. Typical personal traits of the main characters of Gibson’s novels are studied. The description of cyberspace, the term first coined by Gibson, is brought. Novels of Gibson are compared to the ideas of scientific immortalism, the resulting contradictions and disparities arising between them are specified. Literary transhumanism and its functioning in literature are examined in more details. The varieties of transhumanistic art are pointed out. Comparative parallels are conducted between some artistic receptions of science fiction and cyberpunk. As a result, the connection between his cyberpunk works and ideas of transhumanism is determined

Casimir effect with rough metallic mirrors

We calculate the second order roughness correction to the Casimir energy for two parallel metallic mirrors. Our results may also be applied to the plane-sphere geometry used in most experiments. The metallic mirrors are described by the plasma model, with arbitrary values for the plasma wavelength, the mirror separation and the roughness correlation length, with the roughness amplitude remaining the smallest length scale for perturbation theory to hold. From the analysis of the intracavity field fluctuations, we obtain the Casimir energy correction in terms of generalized reflection operators, which account for diffraction and polarization coupling in the scattering by the rough surfaces. We present simple analytical expressions for several limiting cases, as well as numerical results that allow for a reliable calculation of the roughness correction in real experiments. The correction is larger than the result of the Proximity Force Approximation, which is obtained from our theory as a limiting case (very smooth surfaces).Comment: 16 page

Roughness correction to the Casimir force : Beyond the Proximity Force Approximation

We calculate the roughness correction to the Casimir effect in the parallel plates geometry for metallic plates described by the plasma model. The calculation is perturbative in the roughness amplitude with arbitrary values for the plasma wavelength, the plate separation and the roughness correlation length. The correction is found to be always larger than the result obtained in the Proximity Force Approximation.Comment: 7 pages, 3 figures, v2 with minor change

Back-action cancellation in interferometers by quantum locking

We show that back-action noise in interferometric measurements such as gravitational-waves detectors can be completely suppressed by a local control of mirrors motion. An optomechanical sensor with an optimized measurement strategy is used to monitor mirror displacements. A feedback loop then eliminates radiation-pressure effects without adding noise. This very efficient technique leads to an increased sensitivity for the interferometric measurement, which becomes only limited by phase noise. Back-action cancellation is furthermore insensitive to losses in the interferometer.Comment: 4 pages, 3 figures, RevTe

Casimir torque between corrugated metallic plates

We consider two parallel corrugated plates and show that a Casimir torque arises when the corrugation directions are not aligned. We follow the scattering approach and calculate the Casimir energy up to second order in the corrugation amplitudes, taking into account nonspecular reflections, polarization mixing and the finite conductivity of the metals. We compare our results with the proximity force approximation, which overestimates the torque by a factor 2 when taking the conditions that optimize the effect. We argue that the Casimir torque could be measured for separation distances as large as 1 $\mu{\rm m}.$Comment: 7 pages, 3 figures, contribution to QFEXT07 proceeding