4,754 research outputs found
Entanglement Generation from Thermal Spin States via Unitary Beam Splitters
We suggest a method of generating distillable entanglement form mixed states
unitarily, by utilizing the flexibility of dimension od occupied Hilbert space.
We present a model of a thermal spin state entering a beam splitter generating
entanglement. It is the truncation of the state that allows for entanglement
generation. The output entanglement is investigated for different temperatures
and it is found that more randomness - in the form of higher temperature - is
better for this set up.Comment: 4 pages, 3 figures. Small changes in accordance with journal advice
to make more readable. Improved discussion on implemetability of scheme, and
references adde
Entanglement of multiparty stabilizer, symmetric, and antisymmetric states
We study various distance-like entanglement measures of multipartite states
under certain symmetries. Using group averaging techniques we provide
conditions under which the relative entropy of entanglement, the geometric
measure of entanglement and the logarithmic robustness are equivalent. We
consider important classes of multiparty states, and in particular show that
these measures are equivalent for all stabilizer states, symmetric basis and
antisymmetric basis states. We rigorously prove a conjecture that the closest
product state of permutation symmetric states can always be chosen to be
permutation symmetric. This allows us to calculate the explicit values of
various entanglement measures for symmetric and antisymmetric basis states,
observing that antisymmetric states are generally more entangled. We use these
results to obtain a variety of interesting ensembles of quantum states for
which the optimal LOCC discrimination probability may be explicitly determined
and achieved. We also discuss applications to the construction of optimal
entanglement witnesses
The 30/20 GHz communications system functional requirements
The characteristics of 30/20 GHz usage in satellite systems to be used in support of projected communication requirements of the 1990's are defined. A requirements analysis which develops projected market demand for satellite services by general and specialized carriers and an analysis of the impact of propagation and system constraints on 30/20 GHz operation are included. A set of technical performance characteristics for the 30/20 GHz systems which can serve the resulting market demand and the experimental program necessary to verify technical and operational aspects of the proposed systems is also discussed
Thermal robustness of multipartite entanglement of the 1-D spin 1/2 XY model
We study the robustness of multipartite entanglement of the ground state of
the one-dimensional spin 1/2 XY model with a transverse magnetic field in the
presence of thermal excitations, by investigating a threshold temperature,
below which the thermal state is guaranteed to be entangled. We obtain the
threshold temperature based on the geometric measure of entanglement of the
ground state. The threshold temperature reflects three characteristic lines in
the phase diagram of the correlation function. Our approach reveals a region
where multipartite entanglement at zero temperature is high but is thermally
fragile, and another region where multipartite entanglement at zero temperature
is low but is thermally robust.Comment: Revised, 11 pages, 7 figure
Man, Nature, and New Ideas: The Legacy of Sea Pines Plantation
My goal is to learn the history of Hilton Head Island and logically reason out the way it grew, marking Sea Pine’s design influence over time and place. This paper is meant to be a piece of nature and history writing, which has implications for the study of environmental economics and real-estate design practices, but is not strictly about either. The thrust of this piece is the mapping of developmental philosophies and their reflection in the land. This topic interests me because at its core, it looks at how decisions are made, and the trade offs that influence them. The paper is also about the formation of ideas that explore sustainable forms of human-environment interaction, but which do not give up the high quality of life that modern man has come to expect. Environmental issues will continue to influence social, economic and political thought as we move towards midcentury. Sea Pines champions a blending of man and nature that may be able to provide alternative and more efficient solutions to the problems that our society faces
Survival of entanglement in thermal states
We present a general sufficiency condition for the presence of multipartite
entanglement in thermal states stemming from the ground state entanglement. The
condition is written in terms of the ground state entanglement and the
partition function and it gives transition temperatures below which
entanglement is guaranteed to survive. It is flexible and can be easily adapted
to consider entanglement for different splittings, as well as be weakened to
allow easier calculations by approximations. Examples where the condition is
calculated are given. These examples allow us to characterize a minimum gapping
behavior for the survival of entanglement in the thermodynamic limit. Further,
the same technique can be used to find noise thresholds in the generation of
useful resource states for one-way quantum computing.Comment: 6 pages, 2 figures. Changes made in line with publication
recommendations. Motivation and concequences of result clarified, with the
addition of one more example, which applies the result to give noise
thresholds for measurement based quantum computing. New author added with new
result
Relationships between scores on the Jefferson Scale of physician empathy, patient perceptions of physician empathy, and humanistic approaches to patient care: a validity study.
BACKGROUND: Empathy is the backbone of a positive physician-patient relationship. Physician empathy and the patient\u27s awareness of the physician\u27s empathic concern can lead to a more positive clinical outcome.
MATERIAL/METHODS: The Jefferson Scale of Physician Empathy (JSPE) was completed by 36 physicians in the Family Medicine residency program at Thomas Jefferson University Hospital, and 90 patients evaluated these physicians by completing the Jefferson Scale of Patient Perceptions of Physician Empathy (JSPPPE), and a survey about physicians\u27 humanistic approaches to patient care.
RESULTS: A statistically significant correlation was found between scores of the JSPE and JSPPPE (r=0.48, p
CONCLUSIONS: These findings provide further support for the validity of the JSPE. Implications for the assessments of empathy in the physician-patient relationship as related to clinical outcomes are discussed
The EU and the Rights of the Roma: How Could the EU have Changed the French Repatriation Program of 2010?
In August of 2010, the French government began a program of deporting those Roma who lived within the country. Under European Union (EU) law, mass expulsions based on ethnicity are forbidden, as are mass examinations of peoples as opposed to individual assessments in the case of a crime. However, in the spirit of egalitarianism, France does not acknowledge the idea of racial or ethnic minorities. Instead, they have reframed the non- French Roma as a group engaged in criminal activity following Italy’s “security package” of 2008, which described ‘nomads’ as a national security threat and created legislation leading to expulsions of non-Italian Roma. By framing the Roma as a criminal group as opposed to an ethnic minority (that may be engaging in criminal activity), France is able to justify its actions in targeting the Roma people writ large instead of looking at each criminal case on a case-by-case basis. My resulting research question is: if we assume that the Roma are an ethnic minority in France, what obligations does the EU have in enforcing their rights in a member state that does not acknowledge the concept of “ethnic minority”? This paper will look at the French repatriation program and use Critical Race Theory as a framework to critique the situation and examine how EU-level policy could change the position of the Roma in France
New Protocols and Lower Bound for Quantum Secret Sharing with Graph States
We introduce a new family of quantum secret sharing protocols with limited
quantum resources which extends the protocols proposed by Markham and Sanders
and by Broadbent, Chouha, and Tapp. Parametrized by a graph G and a subset of
its vertices A, the protocol consists in: (i) encoding the quantum secret into
the corresponding graph state by acting on the qubits in A; (ii) use a
classical encoding to ensure the existence of a threshold. These new protocols
realize ((k,n)) quantum secret sharing i.e., any set of at least k players
among n can reconstruct the quantum secret, whereas any set of less than k
players has no information about the secret. In the particular case where the
secret is encoded on all the qubits, we explore the values of k for which there
exists a graph such that the corresponding protocol realizes a ((k,n)) secret
sharing. We show that for any threshold k> n-n^{0.68} there exists a graph
allowing a ((k,n)) protocol. On the other hand, we prove that for any k<
79n/156 there is no graph G allowing a ((k,n)) protocol. As a consequence there
exists n_0 such that the protocols introduced by Markham and Sanders admit no
threshold k when the secret is encoded on all the qubits and n>n_0
Neither playing the game nor keeping it real: media logics and Big Brother
Sam Pepper, one of the contestants in Big Brother 11, at one point accused fellow housemates Josie and John James of feigning romantic feelings for each other in order to cash in on lucrative deals with celebrity magazines such as OK! and Hello!. The provocation caused much apparent offence, and led to a prolonged and predominantly rancorous debate about authenticity and inauthenticity, soon extending to revelations that other housemates (Rachel, Corinne) aimed to appear in soft pornography titles like Nuts and Zoo, and as such, ‘couldn’t be trusted’. The clear subtext was that any economic motivation was considered a breach of the rules of the Big Brother game – not the explicit parameters of the competition, but the spirit in which it should be played. Being a worthy winner is a matter of who you are rather than what you do, which raises the question of how we came to know Josie and co, as well as how we come to know celebrity selves generally. If BB has taught us anything about the formation of mediated selves, it is that an authentic mediated self cannot exist – and yet authenticity still matters. This piece reflects on this tension and its implications for our increasingly reflexive media culture
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