2,927 research outputs found

    Thermal and non-thermal signatures of the Unruh effect in Casimir-Polder forces

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    We show that Casimir-Polder forces between two relativistic uniformly accelerated atoms exhibit a transition from the short distance thermal-like behavior predicted by the Unruh effect, to a long distance non-thermal behavior, associated with the breakdown of a local inertial description of the system. This phenomenology extends the Unruh thermal response detected by a single accelerated observer to an accelerated spatially extended system of two particles, and we identify the characteristic length scale for this crossover with the inverse of the proper acceleration of the two atoms. Our results are derived separating at fourth order in perturbation theory the contributions of vacuum fluctuations and radiation reaction field to the Casimir-Polder interaction between two atoms moving in two generic stationary trajectories separated by a constant distance, and linearly coupled to a scalar field. The field can be assumed in its vacuum state or at finite temperature, resulting in a general method for the computation of Casimir-Polder forces in stationary regimes.Comment: 6 pages, 1 figure. Revised versio

    CMOS array design automation techniques

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    A low cost, quick turnaround technique for generating custom metal oxide semiconductor arrays using the standard cell approach was developed, implemented, tested and validated. Basic cell design topology and guidelines are defined based on an extensive analysis that includes circuit, layout, process, array topology and required performance considerations particularly high circuit speed

    Van der Waals and resonance interactions between accelerated atoms in vacuum and the Unruh effect

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    We discuss different physical effects related to the uniform acceleration of atoms in vacuum, in the framework of quantum electrodynamics. We first investigate the van der Waals/Casimir-Polder dispersion and resonance interactions between two uniformly accelerated atoms in vacuum. We show that the atomic acceleration significantly affects the van der Waals force, yielding a different scaling of the interaction with the interatomic distance and an explicit time dependence of the interaction energy. We argue how these results could allow for an indirect detection of the Unruh effect through dispersion interactions between atoms. We then consider the resonance interaction between two accelerated atoms, prepared in a correlated Bell-type state, and interacting with the electromagnetic field in the vacuum state, separating vacuum fluctuations and radiation reaction contributions, both in the free-space and in the presence of a perfectly reflecting plate. We show that nonthermal effects of acceleration manifest in the resonance interaction, yielding a change of the distance dependence of the resonance interaction energy. This suggests that the equivalence between temperature and acceleration does not apply to all radiative properties of accelerated atoms. To further explore this aspect, we evaluate the resonance interaction between two atoms in non inertial motion in the coaccelerated (Rindler) frame and show that in this case the assumption of an Unruh temperature for the field is not required for a complete equivalence of locally inertial and coaccelerated points of views.Comment: 8 pages, Proceedings of the Eighth International Workshop DICE 2016 Spacetime - Matter - Quantum Mechanic

    Assessing the Dimensions of Teacher Attitudes Toward Inclusion: The Development of the TATIS-p

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    A poster describing the development of the Teacher Attitudes Toward Inclusion Survey (TATIS-p)

    Optimisation of photoluminescent painting treatments on different surface layers

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    Improving drivers visibility in night time conditions is vital. Night-time visibility represents one of the most important features of road safety. Within such context, the use of photoluminescent road markings could represent an enhancement with regard to road safety. Consequently, the objective of the investigation here described was confined into the analysis of photoluminescent paints by referring to dense-graded and open-graded friction courses. Measurements, based on photometry technique, were carried out in the laboratory. Cores extracted from the surface layer of known pavements were used. Transitory effects (charge and discharge) and decay phenomena were investigated and modelled as a function of treatment and pavement characteristics (paint quantity, hot mix asphalt volumetrics, etc.). The results highlight that the photoluminescent performance depends on the volumetric characteristics of bituminous mixtures. Results can benefit both researchers and practitioners and can allow optimising painting treatments for different bituminous mixtures

    Resistive relaxation in field-induced insulator-metal transition of a (La0.4_{0.4}Pr0.6_{0.6})1.2_{1.2}Sr1.8_{1.8}Mn2_{2}O7_{7} bilayer manganite single crystal

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    We have investigated the resistive relaxation of a (La0.4_{0.4}Pr0.6_{0.6})1.2_{1.2}Sr1.8_{1.8}Mn2_{2}O7_{7} single crystal, in order to examine the slow dynamics of the field-induced insulator to metal transition of bilayered manganites. The temporal profiles observed in remanent resistance follow a stretched exponential function accompanied by a slow relaxation similar to that obtained in magnetization and magnetostriction data. We demonstrate that the remanent relaxation in magnetotransport has a close relationship with magnetic relaxation that can be understood in the framework of an effective medium approximation by assuming that the first order parameter is proportional to the second order one.Comment: 6 pages,5 figure

    Business model scaling and growth hacking in digital entrepreneurship

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    Creating an innovative product and validating an innovative business model may not be enough for digital startups to be competitive. To grow fast and expand globally, digital startups need to innovate their business model during the scaling phase. A pragmatic approach has recently been proposed to support digital entrepreneurs engaging in business-model innovation during the scaling phase (i.e., business-model scaling), a strategy known as growth hacking. However, we know little about its theoretical grounding and how effective growth hacking is, as businesses lack methodologies to assess its effectiveness before committing resources and investments. To fill this gap, we developed a method for supporting business- model scaling through simulation modeling and provided an illustrative application to the PayPal case. By doing so, we contribute to the ongoing debate on scalability in digital entrepreneurship

    ANALISA PENYEBAB KEMACETAN DI JALAN SLAMET RIYADI (PASAR KUTO) MENUJU ARAH JEMBATAN MUSI 4

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    The traffic jam that occurred on the Slamet Riyadi road towards the Palembang Musi 4 Bridge was due to the large volume of vehicles passing through the road due to the diversion of road users who chose to cross the musi 4 bridge so that the volume of vehicles passing on the road grew day by day, causing even the density level higher and cause congestion during rush hours, namely between 07.00-09.00 WIB, between 12.00-14.00 WIB and between o'clock. 4:00 PM to 6:00 PM WIB.By conducting research and calculations, it is found that the capacity of Slamet Riyadi Street is 2291 SMP / Hour, the worst service level, is F for the morning, occurs on Wednesday and Friday. The worst service level in the afternoon is E. The worst service level in the afternoon is F which occurs on Monday, Tuesday and Thursday, while the capacity of the Major Memet Sastra Wirya Road section is 2291 SMP / Hour and also the worst service level is F for the morning occurs on Friday. The worst service level, D for daytime, occurs on Thursday and Friday. The worst service level for the afternoon is F occurs on Friday.The cause of the congestion that occurs is caused by some roads littered with garbage from landfills, public transports that carry passengers, some roads are used as pedicab bases, many vehicles violate traffic regulations, and others
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