2,376 research outputs found
On universal decoherence under gravity: a perspective through the Equivalence Principle
In Nature Phys. 11, 668 (2015) (Ref. [1]), a composite particle prepared in a
pure initial quantum state and propagated in a uniform gravitational field is
shown to undergo a decoherence process at a rate determined by the
gravitational acceleration. By assuming Einstein's Equivalence Principle to be
valid, we demonstrate, first in a Lorentz frame with accelerating detectors,
and then directly in the Lab frame with uniform gravity, that the dephasing
between the different internal states arise not from gravity but rather from
differences in their rest mass, and the mass dependence of the de Broglie
wave's dispersion relation. We provide an alternative view to the situation
considered by Ref. [1], where we propose that gravity plays a kinematic role in
the loss of fringe visibility by giving the detector a transverse velocity
relative to the particle beam; visibility can be easily recovered by giving the
screen an appropriate uniform velocity. We finally propose that dephasing due
to gravity may in fact take place for certain modifications to the
gravitational potential where the Equivalence Principle is violated.Comment: 5 pages, 3 figure
Quantum variational measurement in the next generation gravitational-wave detectors
A relatively simple method of overcoming the Standard Quantum Limit in the
next-generation Advanced LIGO gravitational wave detector is considered. It is
based on the quantum variational measurement with a single short (a few tens of
meters) filter cavity. Estimates show that this method allows to reduce the
radiation pressure noise at low frequencies () to the level
comparable with or smaller than the low-frequency noises of non-quantum origin
(mirrors suspension noise, mirrors internal thermal noise, and gravity
gradients fluctuations).Comment: 12 pages, 4 figures; NSNS SNR estimates added; misprints correcte
Increasing future gravitational-wave detectors sensitivity by means of amplitude filter cavities and quantum entanglement
The future laser interferometric gravitational-wave detectors sensitivity can
be improved using squeezed light. In particular, recently a scheme which uses
the optical field with frequency dependent squeeze factor, prepared by means of
a relatively short (~30 m) amplitude filter cavity, was proposed
\cite{Corbitt2004-3}. Here we consider an improved version of this scheme,
which allows to further reduce the quantum noise by exploiting the quantum
entanglement between the optical fields at the filter cavity two ports.Comment: 10 pages, 7 figure
A case report of orbital hydatid cyst in Shahrekord
زمینه و هدف: بیماری کیست هیداتید یکی از مهم ترین و شایع ترین بیماری های مشترک انسان و دام است که ناشی از ابتلای انسان به مرحله لاروی انگل اکی نوکوکوس گرانولوزوس (Echinococus granulosus) می باشد. این بیماری با طیف وسیعی از علا یم و یافته های بالینی مشخص می شود که عمدتاً به دلیل درگیر شدن و ایجاد کیست در ارگان های مختلف از جمله کبد، ریه، مغز، طحال و سایر قسمت های بدن می باشد. در موارد کمی نیز کیست در داخل چشم تشکیل شده که کیست هیداتید اربیتال نامیده می شود. با توجه به اینکه این بیماری در استان چهارمحال و بختیاری نسبتاً فراوان است، هدف از گزارش این مورد آشنایی پزشکان با علائم بالینی همراه کیست هیداتید اربیتال می باشد. گزارش مورد: بیمار پسری 11ساله ای است که با پروپتوزیس بدون درد و بدون ضربان مراجعه کرد. در سی تی اسکن ضایعه کیستیک رتروبولبار گزارش شد. بیمار با تشخیص کیست هیداتید بستری و کیست با روش جراحی خارج شد. در آزمایشات پاتولوژی نیز تشخیص کیست هیداتید تأیید گردید. در این بیمار نتیجه درمان رضایت بخش بود و بعد از درمان علایم کاملا بهبود یافت. نتیجه گیری: با توجه به وجود بیماری کیست هیداتید در منطقه، چشم پزشکان باید کیست هیداتید را در تشخیص افتراقی پروپتوز یک طرفه قرار دهند
Energetic Quantum Limit in Large-Scale Interferometers
For each optical topology of an interferometric gravitational wave detector,
quantum mechanics dictates a minimum optical power (the ``energetic quantum
limit'') to achieve a given sensitivity. For standard topologies, when one
seeks to beat the standard quantum limit by a substantial factor, the energetic
quantum limit becomes impossibly large. Intracavity readout schemes may do so
with manageable optical powers.Comment: Revised version; to be published in Proceedings of the 1999 Edoardo
Amaldi Conference on Gravitational Waves; 11 pages including figures;
manuscript is RevTex; figures are .eps; an AIP style file is include
The optical potential of He in the eikonal approximation
The new data of the elastic scattering of He+C at about 40
MeV/nucleon are analyzed in the eikonal approximation. The He+C
phase-shift function is evaluated completely without any {\it ad hoc}
assumption by a Monte Carlo integration, which makes it possible to use a
realistic 6-nucleon wave function for a halo nucleus He. The effect of
the breakup of He on the elastic differential cross sections as well as the
optical potential is studied at different energies from 40 to 800 MeV/nucleon.
PACS number(s): 24.10.-i; 21.60.Ka; 25.60.Bx; 25.10.+s Keywords: Eikonal;
Glauber; Monte Carlo; Halo; BreakupComment: 13 pages, 9 figure
Optimal configurations of filter cavity in future gravitational-wave detectors
Sensitivity of future laser interferometric gravitational-wave detectors can
be improved using squeezed light with frequency-dependent squeeze angle and/or
amplitude, which can be created using additional so-called filter cavities.
Here we compare performances of several variants of this scheme, proposed
during last years, assuming the case of a single relatively short (tens of
meters) filter cavity suitable for implementation already during the life cycle
of the second generation detectors, like Advanced LIGO. Using numerical
optimization, we show that the phase filtering scheme proposed by Kimble et al
[Phys.Rev.D 65, 022002 (2001)] looks as the best candidate for this scenario.Comment: 17 pages, 5 figure
A case of intestinal myiasis due to Sarcophaga hemmoroidalis from Chaharmahal va Bakhtiari province
چکیده: این گزارش مربوط به پسر بچه 13 سالهای است که ساکن روستای سید صالح کوتاه از توابع شهرستان کوهرنگ در استان چهارمحال و بختیاری می باشد. بیمار در شرح حال خود دردهای شکمی در قسمت راست تحتانی، احساس پری شکم، دفع مدفوع شل دو تا سه بار در شبانه روز، کاهش اشتها و کاهش وزن در چند ماه گذشته و همچنین مشاهده کرم های کوچک سفید رنگ متحرک را در مدفوع خود بیان می کرد در هنگام آزمایشات اولیه تعدادی لارو متحرک از مدفوع بیمار جدا و در محلول فرمالین 10 نگهداری شد. سپس با استفاده از کلیدهای تشخیصی و مشاهده خصوصیات مرفولوژی لارو سارکوفاگا هموروئیدالیس (Sarcophaga haemorrhoidalis) تشخیص داده شد
The significance of local thermal non-equilibrium in simulations of enhanced geothermal recovery
International audienceAccessing the thermo-mechanical response of large deep hot dry rock (HDR) reservoirs during geothermal extraction remains a challenging task that can be comprehended with numerical tools. Of crucial im-portance to the economic viability of these HDR reservoirs is the knowledge of thermal output evolution, fluid excessive pressure and induced thermal stress, at various steps of the circulation tests. Thermal recovery from a HDR reservoir, viewed as a deformable fractured medium, is investigated with a focus on the assumption of lo-cal thermal non-equilibrium (LTNE). To this end, a fully coupled finite element formulation for a thermo-elastic fractured medium in LTNE is developed (Gelet et al. 2013). Hydraulic diffusion, thermal diffusion, forced con-vection and deformation are considered in a two-phase framework, the solid phase being made by impermeable solid blocks separated by saturated fractures. Each of the two phases is endowed with its own temperature. The resulting system of equations is used to address a generic HDR reservoir subjected to temperature and pressure gradients. A change of time profile of the outlet fluid temperature is observed as the fracture spacing increases, switching from a single-step pattern to a double-step pattern, a feature which is viewed as characteristic of established LTNE. A dimensionless number is proposed to delineate between local thermal equilibrium (LTE) and non-equilibrium. This number embodies local physical properties of the mixture, elements of the geometry of the reservoir and the production flow rate. All the above properties being fixed, the resulting fracture spacing threshold between LTNE and LTE is found to decrease with increasing porosity. The thermally induced effec-tive stress is tensile near the injection well, illustrating the thermal contraction of the rock, while the pressure contribution of the fracture fluid is negligible during the late period
Transition layer thickness at a fluid-porous interface
The length scale of the transition region between a porous layer and its overlying fluid layer is experimentally studied. The experimental setup consists of a rectangular channel, in which a fluid layer flows over a porous bed. Using particle image velocimetry and refractive index matching, two-dimensional velocity measurements in the interfacial region were performed. The thickness of this transition layer, defined by the height below the permeable interface up to which the velocity decreases to the Darcy scale, is measured and compared with the permeability and the matrix grain size. It was observed that the thickness of the transition zone, δ, is of the order of the grain diameter, and hence, much larger than the square root of the permeability as predicted by previous theoretical studies. The Reynolds number and the fluid height over the porous substrate were found to affect the gradient of the horizontal velocity component at the interfacial region while the length scale of the transition layer remains approximately unchanged. The effect of the porous matrix type has been investigated by utilizing spherical glass beads as well as granulates. Scaling the measured velocities by the interfacial velocity near the uppermost solid matrix resulted in a unique velocity distribution in the case of monodisperse glass beads, hinting that the interfacial velocity represents a proper scaling factor. However, for polydisperse granulate material deviation from this behavior was observed
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