Quantum random walks with decoherent coins

The quantum random walk has been much studied recently, largely due to its highly nonclassical behavior. In this paper, we study one possible route to classical behavior for the discrete quantum walk on the line: the presence of decoherence in the quantum ``coin'' which drives the walk. We find exact analytical expressions for the time dependence of the first two moments of position, and show that in the long-time limit the variance grows linearly with time, unlike the unitary walk. We compare this to the results of direct numerical simulation, and see how the form of the position distribution changes from the unitary to the usual classical result as we increase the strength of the decoherence.Comment: Minor revisions, especially in introduction. Published versio

BERAT POTONG, BERAT KARKAS DAN PERSENTASE KARKAS TERNAK SAPI POTONG LOKAL YANG DIPOTONG DI RUMAH POTONG HEWAN MANADO

SLAUGHTER WEIGHT CARCASS WEIGHT AND THE PERCENTAGE OF CARCASSES OF NORTH SULAWESI LOCAL BEEF CATTLE CUT IN SLAUGHTER.The study aims to determine the slaughter weight, carcass weight  and  the percentage of carcasses of North Sulawesi local beef cattle cut in RPH Manado. The material used in this study were 40 local North Sulawesi beef cattle in RPH, Manado. The equipment used in this study is the meter and the hanging scales. This study uses the method of observation, direct interviews and measurements carried out randomly and weighing to determine the cut weight, carcass weight and carcass percentage. The results showed that the average value of 271,475 kg ± 34,129 kg weight, carcass weight 136,025 kg ± 16,477 and the percentage of North Sulawesi local beef cattle carcass 50,168% ± 1,694. Based on the results of the study it was concluded that the cattle of North Sulawesi local beef cattle slaughtered in RPH Manado still relatively low in term of average weight of slaughter and carcass weight. Keywords: Beef Cattle, Weight, Slaughterhous

Stellar triples with chemically homogeneously evolving inner binaries

Observations suggest that massive stellar triples are common. However, their evolution is not yet fully understood. We investigate the evolution of hierarchical triples in which the stars of the inner binary experience chemically homogeneous evolution (CHE), particularly to understand the role of the tertiary star in the formation of gravitational-wave (GW) sources. We use the triple-star rapid population synthesis code TRES to determine the evolution of these systems at two representative metallicities: $Z = 0.005$ and $Z = 0.0005$. About half of all triples harbouring a CHE inner binary (CHE triples) experience tertiary mass transfer (TMT) episodes, an event which is rare for classically evolving stars. In the majority of TMT episodes, the inner binary consists of two main-sequence stars (58-60 per cent) or two black holes (BHs, 24-31 per cent). Additionally, we explore the role of von Zeipel-Lidov-Kozai (ZLK) oscillations for CHE triples. ZLK oscillations can result in eccentric stellar mergers or lead to the formation of eccentric compact binaries in systems with initial outer pericenters smaller than $\sim$ 1200 $R_{\odot}$. Approximately 24-30 per cent of CHE triples form GW sources, and in 31 per cent of these, the tertiary star plays a significant role and leads to configurations that are not predicted for isolated binaries. We conclude that the evolution of CHE binaries can be affected by a close tertiary companion, resulting in astronomical transients such as BH-BH binaries that merge via GW emission orders of magnitude faster than their isolated binary counterparts and tertiary-driven massive stellar mergers.Comment: 27 pages, 17 figures, 3 tables. Submitted to MNRA

Stellar triples with chemically homogeneously evolving inner binaries

Observations suggest that massive stellar triples are common. However, their evolution is not yet fully understood. We investigatethe evolution of hierarchical triples in which the stars of the inner binary experience chemically homogeneous evolution (CHE),particularly to understand the role of the tertiary star in the formation of gravitational-wave (GW) sources. We use the triple-starrapid population synthesis code TRES to determine the evolution of these systems at two representative metallicities: Z = 0.005and Z = 0.0005. About half of all triples harbouring a CHE inner binary (CHE triples) experience tertiary mass transfer (TMT)episodes, an event which is rare for classically evolving stars. In the majority of TMT episodes, the inner binary consistsof two main-sequence stars (58–60 per cent) or two black holes (BHs, 24–31 per cent). Additionally, we explore the role ofvon Zeipel-Lidov-Kozai (ZLK) oscillations for CHE triples. ZLK oscillations can result in eccentric stellar mergers or lead tothe formation of eccentric compact binaries in systems with initial outer pericentre smaller than ∼ 1200 R. Approximately24–30 per cent of CHE triples form GW sources, and in 31 per cent of these, the tertiary star plays a significant role and leadsto configurations that are not predicted for isolated binaries. We conclude that the evolution of CHE binaries can be affected bya close tertiary companion, resulting in astronomical transients such as BH–BH binaries that merge via GW emission orders ofmagnitude faster than their isolated binary counterparts and tertiary-driven massive stellar merger

Quantum Walks driven by many coins

Quantum random walks have been much studied recently, largely due to their highly nonclassical behavior. In this paper, we study one possible route to classical behavior for the discrete quantum random walk on the line: the use of multiple quantum ``coins'' in order to diminish the effects of interference between paths. We find solutions to this system in terms of the single coin random walk, and compare the asymptotic limit of these solutions to numerical simulations. We find exact analytical expressions for the time-dependence of the first two moments, and show that in the long time limit the ``quantum mechanical'' behavior of the one-coin walk persists. We further show that this is generic for a very broad class of possible walks, and that this behavior disappears only in the limit of a new coin for every step of the walk.Comment: 36 pages RevTeX 4.0 + 5 figures (encapsulated Postscript). Submitted to Physical Review

Coherent Excitation of the Singlet-triplet Mixed 1s4f State of Helium

In this paper, we present a detailed theoretical description for the coherent electron-impact excitation, the subsequent time evolution, and the cascading decay process of the singlet-triplet mixed 1s4f state of helium. The excitation amplitude and phase of each sublevel of this state are related to measurable coincidence intensities and polarizations of the emitted photons. It is found that the intensity and polarization of the emitted photons are time modulated due to the singlet and triplet mixing in the 1s4f state