scholarly journals BOUNDARY DYNAMICS IN DILATON GRAVITY

1994 ◽  
Vol 09 (33) ◽  
pp. 3105-3117 ◽  
Author(s):  
SUMIT R. DAS ◽  
SUDIPTA MUKHERJI
Keyword(s):  
Total Energy ◽  
Finite Interval ◽  
Critical Value ◽  
Matter Wave ◽  
Conformal Anomaly ◽  
Dilaton Gravity ◽  
Matter Energy ◽  
Reparametrization Invariance ◽  
Boundary Dynamics

We study the dynamics of the boundary in two-dimensional dilaton gravity coupled to N massless scalars. We rederive the boundary conditions of Refs. 1 and 3 in a way which makes the requirement of reparametrization invariance and the role of conformal anomaly explicit. We then study the semiclassical behavior of the boundary in the N = 24 theory in the presence of an incoming matter wave with a constant energy flux spread over a finite interval. There is a critical value of the matter energy density below which the boundary is stable and all the matter is reflected back. For energy densities greater than this critical value there is a similar behavior for small values of the total energy thrown in. However, when the total energy exceeds another critical value the boundary exhibits a runaway behavior and the space-time develops singularities and horizons.

scholarly journals Role of thermal field in entanglement harvesting between two accelerated Unruh-DeWitt detectors

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
Dipankar Barman ◽  
Subhajit Barman ◽  
Bibhas Ranjan Majhi
Keyword(s):  
Mutual Information ◽  
Critical Point ◽  
Thermal Field ◽  
Narrow Range ◽  
Critical Value ◽  
Critical Values ◽  
Parallel Motion ◽  
Field Temperature ◽  
The Right

Abstract We investigate the effects of field temperature T(f) on the entanglement harvesting between two uniformly accelerated detectors. For their parallel motion, the thermal nature of fields does not produce any entanglement, and therefore, the outcome is the same as the non-thermal situation. On the contrary, T(f) affects entanglement harvesting when the detectors are in anti-parallel motion, i.e., when detectors A and B are in the right and left Rindler wedges, respectively. While for T(f) = 0 entanglement harvesting is possible for all values of A’s acceleration aA, in the presence of temperature, it is possible only within a narrow range of aA. In (1 + 1) dimensions, the range starts from specific values and extends to infinity, and as we increase T(f), the minimum required value of aA for entanglement harvesting increases. Moreover, above a critical value aA = ac harvesting increases as we increase T(f), which is just opposite to the accelerations below it. There are several critical values in (1 + 3) dimensions when they are in different accelerations. Contrary to the single range in (1 + 1) dimensions, here harvesting is possible within several discrete ranges of aA. Interestingly, for equal accelerations, one has a single critical point, with nature quite similar to (1 + 1) dimensional results. We also discuss the dependence of mutual information among these detectors on aA and T(f).

Ordinary SQUID interferometers and superfluid helium matter wave interferometers: The role of quantum fluctuations

2010 ◽  
Vol 111 (2) ◽  
pp. 332-339 ◽  
Author(s):  
A. I. Golovashkin ◽  
L. N. Zherikhina ◽  
A. M. Tskhovrebov ◽  
G. N. Izmailov ◽  
V. V. Ozolin
Keyword(s):  
Superfluid Helium ◽  
Quantum Fluctuations ◽  
Matter Wave

scholarly journals Role of Mie scattering in the seeding of matter-wave superradiance

2012 ◽  
Vol 86 (4) ◽  
Author(s):  
R. Bachelard ◽  
H. Bender ◽  
Ph. W. Courteille ◽  
N. Piovella ◽  
C. Stehle ◽  
...  
Keyword(s):  
Mie Scattering ◽  
Matter Wave

THE TALENT VERSUS LUCK MODEL AS AN ENSEMBLE OF ONE-DIMENSIONAL RANDOM WALKS

2021 ◽  
Author(s):  
RICARDO SIMÃO ◽  
FRANCISCO ROSENDO ◽  
LUCAS WARDIL
Keyword(s):  
Random Walks ◽  
Critical Value ◽  
One Dimensional ◽  
Sequence Of Events ◽  
Long Run ◽  
Large Fluctuations ◽  
Two Factors ◽  
Individual Success ◽  
Shed Light

The role of luck on individual success is hard to be investigated empirically. Simplified mathematical models are often used to shed light on the subtle relations between success and luck. Recently, a simple model called “Talent versus Luck” showed that the most successful individual in a population can be just an average talented individual that is subjected to a very fortunate sequence of events. Here, we modify the framework of the TvL model such that in our model the individuals’ success is modelled as an ensemble of one-dimensional random walks. Our model reproduces the original TvL results and, due to the mathematical simplicity, it shows clearly that the original conclusions of the TvL model are the consequence of two factors: first, the normal distribution of talents with low standard deviation, which creates a large number of average talented individuals; second, the low number of steps considered, which allows the observation of large fluctuations. We also show that the results strongly depend on the relative frequency of good and bad luck events, which defines a critical value for the talent: in the long run, the individuals with high talent end up very successful and those with low talent end up ruined. Last, we considered two variations to illustrate applications of the ensemble of random walks model.

scholarly journals The Role of Dispersal in Interacting Patches Subject to an Allee Effect

2013 ◽  
Vol 45 (4) ◽  
pp. 1182-1197
Author(s):  
N. Lanchier
Keyword(s):  
Allee Effect ◽  
Interacting Particle Systems ◽  
Local Population ◽  
Critical Value ◽  
Initial Distribution ◽  
Interacting Particle ◽  
Strong Allee Effect ◽  
Long Term Behavior

This article is concerned with a stochastic multipatch model in which each local population is subject to a strong Allee effect. The model is obtained by using the framework of interacting particle systems to extend a stochastic two-patch model that was recently introduced by Kang and the author. The main objective is to understand the effect of the geometry of the network of interactions, which represents potential migrations between patches, on the long-term behavior of the metapopulation. In the limit as the number of patches tends to ∞, there is a critical value for the Allee threshold below which the metapopulation expands and above which the metapopulation goes extinct. Spatial simulations on large regular graphs suggest that this critical value strongly depends on the initial distribution when the degree of the network is large, whereas the critical value does not depend on the initial distribution when the degree is small. Looking at the system starting with a single occupied patch on the complete graph and on the ring, we prove analytical results that support this conjecture. From an ecological perspective, these results indicate that, upon arrival of an alien species subject to a strong Allee effect to a new area, though dispersal is necessary for its expansion, fast long-range dispersal drives the population toward extinction.

Effects of TiO2 on the Viscocity and Solidification Temperature of Mold Fluxes for the Stainless Steel

2011 ◽  
Vol 189-193 ◽  
pp. 107-113 ◽  
Author(s):  
Li Feng Sun ◽  
Hong Po Wang ◽  
Mao Fa Jiang ◽  
Qi Zeng Lin ◽  
Chun Lai Liu ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Critical Value ◽  
Solidification Temperature ◽  
Network Modifier ◽  
Mold Fluxes ◽  
Rotary Viscometer

Effects of TiO2 on the viscous characteristic of mold fluxes for the stainless steel were investigated by the rotary viscometer, TEM and XRD. The results showed that with the increasing amount of additive TiO2, the viscosity and solidification temperature of mold fluxes could decrease gradually, and then increase rapidly. The viscosity and solidification temperature of mold fluxes were minimum of 0.30Pa.s (1300°С ) and 1198°С respectively, as amount of additive TiO2 was 10mass%. The viscosity of mold fluxes could be decreased by the additive TiO2 which played the role of network modifier, and could be increased by the precipitation of perovskite (CaTiO3) crystals as amount of additive TiO2 was more than the critical value. The growth of cuspidine and wollastonite crystals could be restrained, and the precipitation of perovskite and melilite crystals could be promoted by the additive TiO2. In this study, the solubility of additive TiO2 was more than 20mass% in mold fluxes at 1350°С .

scholarly journals Role of nonspherical double counting in DFT+DMFT: Total energy and structural optimization of pnictide superconductors

2018 ◽  
Vol 97 (20) ◽  
Author(s):  
Oleg Kristanovski ◽  
Alexander B. Shick ◽  
Frank Lechermann ◽  
Alexander I. Lichtenstein
Keyword(s):  
Structural Optimization ◽  
Total Energy ◽  
Double Counting ◽  
Pnictide Superconductors

scholarly journals O8A.5 Total energy expenditure and risk of lymphoma subtypes: results from the european epilymph case-control study

2019 ◽  
Vol 76 (Suppl 1) ◽  
pp. A71.2-A71
Author(s):  
Pierluigi Cocco
Keyword(s):  
Physical Activity ◽  
Energy Expenditure ◽  
Total Energy ◽  
Case Control Study ◽  
B Cell Lymphoma ◽  
Case Control ◽  
Total Energy Expenditure ◽  
Recreational Physical Activity ◽  
Control Study

IntroductionPhysical activity is known to convey protection against several cancers, but results on risk of lymphoma and its subtypes have been inconsistent. A possible reason might be confounding by workplace exposures associated with occupational energy expenditure, which was not considered in studies of recreational physical activity. It is also unclear whether energy expenditure acts directly, or through preventing obesity.ObjectivesTo investigate the role of energy expenditure, including occupational and recreational physical activity, on risk of lymphoma subtypes.Materials and methodsBased on questionnaire information on lifetime recreational physical activity and lifetime occupational history available for all participants to the multicenter EpiLymph case-control study, we estimated energy expenditure at work by occupational ISCO68 code, and we applied it to the work histories of study subjects. We also categorized hours of lifetime recreational physical activity into quartiles. We calculated risk of lymphoma subtypes with unconditional polytomous regression analysis, associated with increasing categories of lifetime energy expenditure at work (EEW), increasing categories of recreational physical activity (RPA), and their interaction term (total energy expenditure, TEE), adjusting by age, gender, education, body mass index (BMI), and history of farm work and solvents use.ResultsRisk of lymphoma overall, diffuse large B cell lymphoma and multiple myeloma was not associated with EEW, RPA and TEE. Risk of follicular lymphoma and chronic lymphocytic leukemia associated were elevated with medium and high EEW (OR 3.1, 95% CI 1.5–6.1; (OR 2.5 95% CI 1.2–5.1, respectively), but there was not a significant upward trend.ConclusionsFurther epidemiologic and mechanistic research is warranted to assess the role of physical activity in the etiology of lymphoma subtypes. New standardized energy expenditure assessment methods, as the ones herein developed, might contribute to a better understanding of the nature of the observed inconsistent findings.

scholarly journals TIME IN COSMOLOGY

1999 ◽  
Vol 08 (01) ◽  
pp. 1-22 ◽  
Author(s):  
R. BROUT ◽  
R. PARENTANI
Keyword(s):  
Total Energy ◽  
Scale Factor ◽  
Matrix Elements ◽  
Temporal Dependence ◽  
Radiative Processes ◽  
Fixed Energy ◽  
Transition Matrix Elements ◽  
In Virtue Of ◽  
The Universe ◽  
Reparametrization Invariance

The notion of time in cosmology is revealed through an examination of transition matrix elements of radiative processes occurring in the cosmos. To begin with, the very concept of time is delineated in classical physics in terms of correlations between the succession of configurations which describe a process and a standard trajectory called the clock. The total is an isolated system of fixed energy. This is relevant for cosmology in that the universe is an isolated system which we take to be homogeneous and isotropic. Furthermore, in virtue of the constraint which arises from reparametrization invariance of time, it has zero total energy. Therefore the momentum of the scale factor is determined from the energy of matter. In the quantum theory this is exploited through the use of WKB approximation for the wave function of the scale factor, justified for a large universe. The formalism then gives rise to matrix elements describing matter processes. These are shown to take on the form of usual time dependent quantum amplitudes wherein the temporal dependence is given by a background which is once more fixed by the total energy of matter.

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