Spectral splits of neutrinos as a BCS-BEC crossover type phenomenon

We show that the spectral split of a neutrino ensemble which initially consists of electron type neutrinos, is analogous to the BCS-BEC crossover already observed in ultra cold atomic gas experiments. Such a neutrino ensemble mimics the deleptonization burst of a core collapse supernova. Although these two phenomena belong to very different domains of physics, the propagation of neutrinos from highly interacting inner regions of the supernova to the vacuum is reminiscent of the evolution of Cooper pairs between weak and strong interaction regimes during the crossover. The Hamiltonians and the corresponding many-body states undergo very similar transformations if one replaces the pair quasispin of the latter with the neutrino isospin of the former.Comment: 9 pages, 5 figure

The equilibrium states of open quantum systems in the strong coupling regime

In this work we investigate the late-time stationary states of open quantum systems coupled to a thermal reservoir in the strong coupling regime. In general such systems do not necessarily relax to a Boltzmann distribution if the coupling to the thermal reservoir is non-vanishing or equivalently if the relaxation timescales are finite. Using a variety of non-equilibrium formalisms valid for non-Markovian processes, we show that starting from a product state of the closed system = system + environment, with the environment in its thermal state, the open system which results from coarse graining the environment will evolve towards an equilibrium state at late-times. This state can be expressed as the reduced state of the closed system thermal state at the temperature of the environment. For a linear (harmonic) system and environment, which is exactly solvable, we are able to show in a rigorous way that all multi-time correlations of the open system evolve towards those of the closed system thermal state. Multi-time correlations are especially relevant in the non-Markovian regime, since they cannot be generated by the dynamics of the single-time correlations. For more general systems, which cannot be exactly solved, we are able to provide a general proof that all single-time correlations of the open system evolve to those of the closed system thermal state, to first order in the relaxation rates. For the special case of a zero-temperature reservoir, we are able to explicitly construct the reduced closed system thermal state in terms of the environmental correlations.Comment: 20 pages, 2 figure

Quantum and classical fluctuation theorems from a decoherent histories, open-system analysis

In this paper we present a first-principles analysis of the nonequilibrium work distribution and the free energy difference of a quantum system interacting with a general environment (with arbitrary spectral density and for all temperatures) based on a well-understood micro-physics (quantum Brownian motion) model under the conditions stipulated by the Jarzynski equality [C. Jarzynski, Phys. Rev. Lett. 78, 2690 (1997)] and Crooks' fluctuation theorem [G. E. Crooks, Phys. Rev. E 60, 2721 (1999)] (in short FTs). We use the decoherent history conceptual framework to explain how the notion of trajectories in a quantum system can be made viable and use the environment-induced decoherence scheme to assess the strength of noise which could provide sufficient decoherence to warrant the use of trajectories to define work in open quantum systems. From the solutions to the Langevin equation governing the stochastic dynamics of such systems we were able to produce formal expressions for these quantities entering in the FTs, and from them prove explicitly the validity of the FTs at the high temperature limit. At low temperatures our general results would enable one to identify the range of parameters where FTs may not hold or need be expressed differently. We explain the relation between classical and quantum FTs and the advantage of this micro-physics open-system approach over the phenomenological modeling and energy-level calculations for substitute closed quantum systems

Effect of fly ash on rebars bond strength in the expanded clay aggregate lightweight concrete [Wp?yw popio?u lotnego na wi?zanie pr?tów zbrojeniowych w betonie lekkim z kruszywem z ekspandowanej gliny]

[No abstract available

Determination of Effect of Different Sowing Dates on Oil Content and Fatty Acid Composition in Cameiina (Camelina sativa (L) Crantz) under Ankara Ecological Condition

Bu çalijma, Ankara ekolojik kojullannda 2010-2011 yiii vejetasyon döneminde 8 farkh ekim zaman m ketencik {Camelina sativa (L.) Crantz) bitkisinin yagverimi,yagorani ve bilejenleri üzerine etkisi ni belirlemek amaciyla yürütülmüjtür. Denemede8farkli ekimzamani olarak; 2010yilindaki 1 Ekim(l), 15 Ekim(2), 1 Kasim(3), 15 Kasim (4)ve 2011yihndaki 15 Mart (5), 1 Nisan(6), 15Nisan(7) ile 1 Mayis (8) tarihieri kullanilmiçtir. Deneme Tesadüf BLoklan d eneme desenine göre üc tekerrürlü olarak kurulmuçtur. Ara 5tirmada 8 farkli ekim zamanmm, yag verimi (kg/da),ya|orani (%)ve yagasidikompozisyonuna etkisi beiirlenmi5tir. Çahjmada, ekim zamanlarma bagli yag verimi 0,32-129,78 kg/da ve yag orani ise % 20,57-39,47 arasinda degijtigi görüimüjtür. En yüksek yag verimi 129,78 kg/da ile 1. ekim zamanmdan almmijtir. Ayni 5e kilde en yüksek yag orani % 39,47 ile 4. ekim zaman mdan a Immijtir. Tüm ekim zamanlan için a na yag asitlerilinolenik asit (% 24,86-32,26), linole i k (% 18,45-23,36), oleik (% 16,03-17,59) ve palmitik (% 5,89-7,04) asittir.The research was conducted to determine the oil yield, oil content and fatty a cid composition of different sowing dates in false flax (Come//nosot(\/o(L.) Crantz) under Ankara dried condition in 2010-2011 vegetation season. SowingdateswereOctoberl, October 15, November land November 15 in 2010, and March 15, April 1, April 15 and Maylin 2011. In thisstudythe experimental design was randomized complete block design with three replications. In research, the oil yield (kg/da), oil content (%) and fatty a cid componenets were examined in differentsowingdates. The va lues of oil content (%), oil yield (kg/da) among the different sowing dates ranged from 20,57 to 39,47% and 0,32 to 129,78 kg/da, respectively. Accordingto the result of this research, the first sowing date gave the highest va lue of the oil yield (129,78 kg/da). The highest oil content (39,47) was also recorded for the fourthsowingdate. Fatty adds, I inolenic add (24,86-32,26%), I inoleic acid (18,45-23,36 %), oleic acid (16,03-17,59 %) and palmitic acid (5,89-7,04 5%), were main oil components forall sowing dates

The role of motivation between perceived teacher support and student engagement in science class

This study aimed to investigate the relationships among the middle school students’ perceptions of science teacher support, students’ motivation and students’ engagement in learning science. Student motivation was addressed with task value and academic self-concept while student engagement included aspects of agentic, behavioural, emotional and cognitive engagement. In the study, survey method was used and the data were collected though previously validated self-report questionnaires. Valid data were obtained from 1006 middle school students enrolled in one of the nine public schools in Turkey. The path analysis revealed that perceived science teacher’s support positively predicted students’ task value and academic self-concept in science. Furthermore, students who reported high levels of task value and academic self-concept showed higher levels of engagement in science. Accordingly, it seems important for science teachers to listen to the students, behave fairly and help them to solve their problems in order to motivate them for learning science and increase their engagement in science class. © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group