167 research outputs found
Non-Markovian decoherence in the adiabatic quantum search algorithm
We consider an adiabatic quantum algorithm (Grover's search routine) weakly
coupled to a rather general environment, i.e., without using the Markov
approximation. Markovian errors generally require high-energy excitations (of
the reservoir) and tend to destroy the scalability of the adiabatic quantum
algorithm. We find that, under appropriate conditions (such as low
temperatures), the low-energy (i.e., non-Markovian) modes of the bath are most
important. Hence the scalability of the adiabatic quantum algorithm depends on
the infra-red behavior of the environment: a reasonably small coupling to the
three-dimensional electromagnetic field does not destroy the scaling behavior,
whereas phonons or localized degrees of freedom can be problematic. PACS:
03.67.Pp, 03.67.Lx, 03.67.-a, 03.65.Yz
Shakhbazian compact galaxy groups. II. Photometric and spectroscopic study of ShCG 376
The results of the redshift measurements and of the detailed surface
photometry in BVR of the compact group ShCG 376 are presented. The radial
velocity dispersion, the virial mass, the total luminosity, the M/L ratio, and
the crossing time of the group are estimated. The group consists of eight
accordant redshift spiral galaxies. Four (or possibly five) of the group
members have emission-line spectra. Such morphological content and the number
of emission-line galaxies are very atypical for compact galaxy groups. There
are signs of interaction between some members of the group. It is suggested
that the irregular shape of the brightest galaxy No. 4 is probably due to
interaction with other members of the group, particularly, the emission line
galaxy No. 6 with a discordant redshift (Delta v = 2600 km/s). It is speculated
that the latter galaxy may be a infalling intruder to the group.Comment: accepted A&A, 7 pages, 6 figures are in separate file
The Properties of the Heterogeneous Shakhbazyan Groups of Galaxies in the SDSS
We present a systematic study of the sub-sample of Shakhbazyan groups (SHKs)
covered by the Sloan Digital Sky Survey Data Release--5 (SDSS-5). SHKs probe an
environment with characteristics which are intermediate between those of loose
and very compact groups. Surprisingly, we found that several groups identifying
algorithms (e.g. Berlind et al. 2006, Tago et al. 2008) miss this type of
structures. Using the SDSS-5 spectroscopic data and the photometric redshifts
derived in D'Abrusco et al. 2007, we identified possible group members in
photometric redshift space and derived, for each group, several individual
properties. We also combined pointed and stacked Rosat All Sky Survey data to
investigate the X-ray luminosities of these systems. Our study confirms that
the majority of groups are physical entities with richness in the range 3--13
galaxies, and properties ranging between those of loose and compact groups. We
confirm that SHK groups are richer in early-type galaxies than the surrounding
environment and the field, as expected from the morphology-density relation and
from the selection of groups of red galaxies. Furthermore, our work supports
the existence of two sub-classes of structures, the first one being formed by
compact and isolated groups and the second formed by extended structures. We
suggest that while the first class of objects dwells in less dense regions like
the outer parts of clusters or the field, possibly sharing the properties of
Hickson Compact Groups, the more extended structures represent a mixture of
[core+halo] configurations and cores of rich clusters. X-ray luminosities for
SHKs are generally consistent with these results and with the expectations for
the L_X-sigma_v relation, but also suggest the velocity dispersions reported in
literature are underestimated for some of the richest systems.Comment: 20 pages, 14 figures, 4 tables. Accepted for publication by MNRA
Toward quantum simulations of biological information flow
Recent advances in the spectroscopy of biomolecules have highlighted the
possibility of quantum coherence playing an active role in biological energy
transport. The revelation that quantum coherence can survive in the hot and wet
environment of biology has generated a lively debate across both the physics
and biology communities. In particular, it remains unclear to what extent
non-trivial quantum effects are utilised in biology and what advantage, if any,
they afford. We propose an analogue quantum simulator, based on currently
available techniques in ultra-cold atom physics, to study a model of energy and
electron transport based on the Holstein Hamiltonian By simulating the salient
aspects of a biological system in a tunable laboratory setup, we hope to gain
insight into the validity of several theoretical models of biological quantum
transport in a variety of relevant parameter regimes.Comment: 8 Pages, 2 Figures, Non-technical contributing article for the
Interface Focus Theme Issue `Computability and the Turning centenary'.
Interface Focus
http://rsfs.royalsocietypublishing.org/content/early/2012/03/22/rsfs.2011.0109.shor
Entanglement evolution in finite dimensions
We provide a relation which describes how the entanglement of two d-level
systems evolves as either system undergoes an arbitrary physical process. The
dynamics of the entanglement turns out to be of a simple form, and is fully
captured by a single quantity.Comment: 4 pages, 1 figure; new title and introduction, added references, some
makeup; published versio
Design and Cost Analysis of a Self-contained Mobile Laboratory for Commercial-scale Aquatic Species Cryopreservation
© Copyright by the World Aquaculture Society 2018 Although aquatic species cryopreservation protocols have been studied around the world over the past 60 yr., germplasm repository development efforts and commercialization have begun only recently. The goal of this project was to develop a self-contained mobile laboratory for on-site high-throughput cryopreservation of aquatic species. The objectives of this study were to: (1) identify how a mobile laboratory would function in different operational scenarios, (2) customize an enclosed cargo trailer to function as a mobile laboratory, (3) evaluate the laboratory layout and ability of cryopreservation equipment to operate from generator power, and (4) document the investment costs for private and public groups to integrate a mobile laboratory into an existing cryopreservation facility at three levels of automation and estimate the total cost per trip based on hypothetical assumptions for two scenarios (aquaculture production and repository development). There were three operational designs identified for the mobile laboratory: (1) self-contained work inside the unit using generator power, (2) work inside the unit using external facility power, and (3) using the equipment inside of a host facility. The investment costs for a base-level mobile laboratory ranged between US5787 for private groups and between US5315 for public groups. With the addition of a range of automated processing equipment, total investment costs ranged from US103,529 for private groups and US94,891 for public groups. The total cost per trip to cryopreserve sperm of 59 blue catfish, Ictalurus furcatus, males to produce 6300 0.5-mL French straws was estimated to range from US14,633 for private and between US16,938 for public groups depending on the level of automation. Total cost per trip to cryopreserve sperm of 500 males of five different species in the genus Xiphophorus to produce 641 0.25-mL French straws was estimated to range from US7640 for private and US8088 for public groups depending on level of automation. Overall, a commercial-scale mobile laboratory was developed that can assist current germplasm activities and support future repository and industry development, and the layout information provided can help others to design and build comparable units
Approaches to Measuring Entanglement in Chemical Magnetometers
Chemical magnetometers are radical pair systems such as solutions of pyrene and N,N-dimethylaniline (Py–DMA) that show magnetic field effects in their spin dynamics and their fluorescence. We investigate the existence and decay of quantum entanglement in free geminate Py–DMA radical pairs and discuss how entanglement can be assessed in these systems. We provide an entanglement witness and propose possible observables for experimentally estimating entanglement in radical pair systems with isotropic hyperfine couplings. As an application, we analyze how the field dependence of the entanglement lifetime in Py–DMA could in principle be used for magnetometry and illustrate the propagation of measurement errors in this approach
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