1,132 research outputs found
His story/her story: A dialogue about including men and masculinities in the women’s studies curriculum
The article discusses the issue of inclusion of men and masculinities in the Women\u27s Studies curriculum. Women\u27s Studies programs were started to compensate for the male domination in the academics. Women\u27s Studies presented a platform where scholarship for women was produced and taken seriously, female students and faculty could find their say or voice, and theoretical investigations required for the advancement of the aims of the women\u27s movement could take place. If the academy as a whole does not sufficiently integrate Women\u27s Studies into the curriculum, integrating Men\u27s Studies into Women\u27s Studies might end up further marginalizing Women\u27s Studies by decreasing the number of classroom hours students spend engaging women\u27s lives and feminist scholarship. Such an integration would presents an another form of male privilege, with men manipulating their way into the only branch of scholarship that has consistently focused on women. On a ground level, feminist scholars are apprehensive that a move from a Women\u27s Studies program to a Gender Studies program will reduce the political aspect of women\u27s programs
Side-channel-free quantum key distribution
Quantum key distribution (QKD) offers the promise of absolutely secure
communications. However, proofs of absolute security often assume perfect
implementation from theory to experiment. Thus, existing systems may be prone
to insidious side-channel attacks that rely on flaws in experimental
implementation. Here we replace all real channels with virtual channels in a
QKD protocol, making the relevant detectors and settings inside private spaces
inaccessible while simultaneously acting as a Hilbert space filter to eliminate
side-channel attacks. By using a quantum memory we find that we are able to
bound the secret-key rate below by the entanglement-distillation rate computed
over the distributed states.Comment: Considering general quantum systems, we extended QKD to the presence
of an untrusted relay, whose measurement creates secret correlations in
remote stations (achievable rate lower-bounded by the coherent information).
This key ingredient, i.e., the use of a measurement-based untrusted relay,
has been called 'measurement-device independence' in another arXiv submission
(arXiv:1109.1473
Limitations of entropic inequalities for detecting nonclassicality in the postselected Bell causal structure
Classical and quantum physics impose different constraints on the joint
probability distributions of observed variables in a causal structure. These
differences mean that certain correlations can be certified as non-classical,
which has both foundational and practical importance. Rather than working with
the probability distribution itself, it can instead be convenient to work with
the entropies of the observed variables. In the Bell causal structure with two
inputs and outputs per party, a technique that uses entropic inequalities is
known that can always identify non-classical correlations. Here we consider the
analogue of this technique in the generalization of this scenario to more
outcomes. We identify a family of non-classical correlations in the Bell
scenario with two inputs and three outputs per party whose non-classicality
cannot be detected through the direct analogue of the previous technique. We
also show that use of Tsallis entropy instead of Shannon entropy does not help
in this case. Furthermore, we give evidence that natural extensions of the
technique also do not help. More precisely, our evidence suggests that even if
we allow the observed correlations to be post-processed according to a natural
class of non-classicality non-generating operations, entropic inequalities for
either the Shannon or Tsallis entropies cannot detect the non-classicality, and
hence that entropic inequalities are generally not sufficient to detect
non-classicality in the Bell causal structure. In addition, for the bipartite
Bell scenario with two inputs and three outputs we find the vertex description
of the polytope of non-signalling distributions that satisfy all of the
CHSH-type inequalities, which is one of the main regions of investigation in
this work.Comment: 14+7 pages, 3 figures, v2: new results added and parts of the text
restructured, v3: version accepted for publication (title differs from
published version due to editorial convention
Is Quantum Bit Commitment Really Possible?
We show that all proposed quantum bit commitment schemes are insecure because
the sender, Alice, can almost always cheat successfully by using an
Einstein-Podolsky-Rosen type of attack and delaying her measurement until she
opens her commitment.Comment: Major revisions to include a more extensive introduction and an
example of bit commitment. Overlap with independent work by Mayers
acknowledged. More recent works by Mayers, by Lo and Chau and by Lo are also
noted. Accepted for publication in Phys. Rev. Let
\u3ci\u3eParavitellotrema overstreeti\u3c/i\u3e Sp. n. (Digenea: Hemiuridae) from the Colombian Freshwater Stingray \u3ci\u3ePotamotrygon magdalenae\u3c/i\u3e Dumeri
Paravitellotrema overstreeti from the freshwater stingray Potamotrygon magdalenae in northern Colombia most closely resembles P. thorsoni by possessing a muscular sinus organ and sinus sac as well as exhibiting a saccate rather than elongate prostatic vesicle, It differs by possessing lobate rather than spherical vitellaria, a smaller sinus organ and sinus sac, elongate rather than diamond-shaped prostatic cells enclosed in a delicate membrane rather than free in the parenchyma, and a metraterm joining the hermaphroditic duct immediately anterior to the prostatic vesicle rather than at the base of the sinus organ
\u3ci\u3eParavitellotrema overstreeti\u3c/i\u3e Sp. n. (Digenea: Hemiuridae) from the Colombian Freshwater Stingray \u3ci\u3ePotamotrygon magdalenae\u3c/i\u3e Dumeri
Paravitellotrema overstreeti from the freshwater stingray Potamotrygon magdalenae in northern Colombia most closely resembles P. thorsoni by possessing a muscular sinus organ and sinus sac as well as exhibiting a saccate rather than elongate prostatic vesicle, It differs by possessing lobate rather than spherical vitellaria, a smaller sinus organ and sinus sac, elongate rather than diamond-shaped prostatic cells enclosed in a delicate membrane rather than free in the parenchyma, and a metraterm joining the hermaphroditic duct immediately anterior to the prostatic vesicle rather than at the base of the sinus organ
Self-Testing of Physical Theories, or, Is Quantum Theory Optimal with Respect to Some Information-Processing Task?
Self-testing usually refers to the task of taking a given set of observed
correlations that are assumed to arise via a process that is accurately
described by quantum theory, and trying to infer the quantum state and
measurements. In other words it is concerned with the question of whether we
can tell what quantum black-box devices are doing by looking only at their
input-output behaviour and is known to be possible in several cases. Here we
introduce a more general question: is it possible to self-test a theory, and,
in particular, quantum theory? More precisely, we ask whether within a
particular causal structure there are tasks that can only be performed in
theories that have the same correlations as quantum mechanics in any scenario.
We present a candidate task for such a correlation self-test and analyse it in
a range of generalised probabilistic theories (GPTs), showing that none of
these perform better than quantum theory. A generalisation of our results
showing that all non-quantum GPTs are strictly inferior to quantum mechanics
for this task would point to a new way to axiomatise quantum theory, and enable
an experimental test that simultaneously rules out such GPTs.Comment: 6 pages; v2: close to published version; v3: typos correcte
Ares I Stage Separation System Design Certification Testing
NASA is committed to the development of a new crew launch vehicle, the Ares I, that can support human missions to low Earth orbit (LEO) and the moon with unprecedented safety and reliability. NASA's Constellation program comprises the Ares I and Ares V launch vehicles, the Orion crew vehicle, and the Altair lunar lander. Based on historical precedent, stage separation is one of the most significant technical and systems engineering challenges that must be addressed in order to achieve this commitment. This paper surveys historical separation system tests that have been completed in order to ensure staging of other launch vehicles. Key separation system design trades evaluated for Ares I include single vs. dual separation plane options, retro-rockets vs. pneumatic gas actuators, small solid motor quantity/placement/timing, and continuous vs. clamshell interstage configuration options. Both subscale and full-scale tests are required to address the prediction of complex dynamic loading scenarios present during staging events. Test objectives such as separation system functionality, and pyroshock and debris field measurements for the full-scale tests are described. Discussion about the test article, support infrastructure and instrumentation are provided
Quantum information cannot be split into complementary parts
We prove a new impossibility for quantum information (the no-splitting
theorem): an unknown quantum bit (qubit) cannot be split into two complementary
qubits. This impossibility, together with the no-cloning theorem, demonstrates
that an unknown qubit state is a single entity, which cannot be cloned or
split. This sheds new light on quantum computation and quantum information.Comment: 9 pages, 1 figur
Alternative schemes for measurement-device-independent quantum key distribution
Practical schemes for measurement-device-independent quantum key distribution
using phase and path or time encoding are presented. In addition to immunity to
existing loopholes in detection systems, our setup employs simple encoding and
decoding modules without relying on polarization maintenance or optical
switches. Moreover, by employing a modified sifting technique to handle the
dead-time limitations in single-photon detectors, our scheme can be run with
only two single-photon detectors. With a phase-postselection technique, a
decoy-state variant of our scheme is also proposed, whose key generation rate
scales linearly with the channel transmittance.Comment: 30 pages, 5 figure
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