1,808 research outputs found
Device-independent bounds for Hardy's experiment
In this Letter we compute an analogue of Tsirelson's bound for Hardy's test
of nonlocality, that is, the maximum violation of locality constraints allowed
by the quantum formalism, irrespective of the dimension of the system. The
value is found to be the same as the one achievable already with two-qubit
systems, and we show that only a very specific class of states can lead to such
maximal value, thus highlighting Hardy's test as a device-independent self-test
protocol for such states. By considering realistic constraints in Hardy's test,
we also compute device-independent upper bounds on this violation and show that
these bounds are saturated by two-qubit systems, thus showing that there is no
advantage in using higher-dimensional systems in experimental implementations
of such test.Comment: 4 pages, 2 figure
The reported use and effectiveness of Hypericum (St Johnâs wort) on affective symptoms in a depression self-help group
A recent meta-analysis suggested that Hypericum
perforatum (St Johnâs wort) is an effective
treatment for mild to moderate depression and
may have a superior side-effect profile to some
antidepressant drugs. The aim of this study was to
assess the use of herbal remedies in treating
depressive and anxiety symptoms, as reported by
members of the UK self-help organization
Depression Alliance using self-completed
questionnaires. More than 50% of the 452
respondents reported using Hypericum, onequarter
of whom also reported concurrent use of
traditional antidepressants. Most of the sample
reported sufficient symptoms for warranting a
diagnosis of major depression, with the majority
also describing symptoms suggestive of co-morbid
psychiatric conditions. One-half of the Hypericum
users experienced symptom improvement, which
for most occurred within the first 4 weeks of use.
Response was better for those with mild as
compared to severe symptoms and poorer for
those taking Hypericum alongside other
antidepressants. The responders were generally
older than non-responders. Adverse effects were
reported by one-quarter of users and were mostly
psychological in nature. This retrospective survey
indicated that use of herbal remedies was
common in this population. Although often helpful
in relieving symptoms, particularly in those with
mild depression, there is a risk of adverse events
and drug interaction
Coin Tossing is Strictly Weaker Than Bit Commitment
We define cryptographic assumptions applicable to two mistrustful parties who
each control two or more separate secure sites between which special relativity
guarantees a time lapse in communication. We show that, under these
assumptions, unconditionally secure coin tossing can be carried out by
exchanges of classical information. We show also, following Mayers, Lo and
Chau, that unconditionally secure bit commitment cannot be carried out by
finitely many exchanges of classical or quantum information. Finally we show
that, under standard cryptographic assumptions, coin tossing is strictly weaker
than bit commitment. That is, no secure classical or quantum bit commitment
protocol can be built from a finite number of invocations of a secure coin
tossing black box together with finitely many additional information exchanges.Comment: Final version; to appear in Phys. Rev. Let
His story/her story: A dialogue about including men and masculinities in the womenâs 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
Effects of detector efficiency mismatch on security of quantum cryptosystems
We suggest a type of attack on quantum cryptosystems that exploits variations
in detector efficiency as a function of a control parameter accessible to an
eavesdropper. With gated single-photon detectors, this control parameter can be
the timing of the incoming pulse. When the eavesdropper sends short pulses
using the appropriate timing so that the two gated detectors in Bob's setup
have different efficiencies, the security of quantum key distribution can be
compromised. Specifically, we show for the Bennett-Brassard 1984 (BB84)
protocol that if the efficiency mismatch between 0 and 1 detectors for some
value of the control parameter gets large enough (roughly 15:1 or larger), Eve
can construct a successful faked-states attack causing a quantum bit error rate
lower than 11%. We also derive a general security bound as a function of the
detector sensitivity mismatch for the BB84 protocol. Experimental data for two
different detectors are presented, and protection measures against this attack
are discussed.Comment: v3: identical to the journal version. However, after publication we
have discovered that Eq. 11 is incorrect: the available bit rate after
privacy amplification is reduced even in the case (QBER)=0 [see Quant. Inf.
Comp. 7, 73 (2007)
Unconditionally Secure Key Distribution Based on Two Nonorthogonal States
We prove the unconditional security of the Bennett 1992 protocol, by using a
reduction to an entanglement distillation protocol initiated by a local
filtering process. The bit errors and the phase errors are correlated after the
filtering, and we can bound the amount of phase errors from the observed bit
errors by an estimation method involving nonorthogonal measurements. The angle
between the two states shows a trade-off between accuracy of the estimation and
robustness to noises.Comment: 5 pages, 1 figur
ImmunoCap 250 for Diagnostics of Allergy and Autoimmunity
As HLS EU International coordinator, I have planned and led DMUglobal trips for students and staff in 2019 and 2020 to Vilnius Life Science Centre and the COINS Life Science conference, this poster has been presented at this conference in 2020.See Abstract Booklet p.4
Security Trade-offs in Ancilla-Free Quantum Bit Commitment in the Presence of Superselection Rules
Security trade-offs have been established for one-way bit commitment in
quant-ph/0106019. We study this trade-off in two superselection settings. We
show that for an `abelian' superselection rule (exemplified by particle
conservation) the standard trade-off between sealing and binding properties
still holds. For the non-abelian case (exemplified by angular momentum
conservation) the security trade-off can be more subtle, which we illustrate by
showing that if the bit-commitment is forced to be ancilla-free an
asymptotically secure quantum bit commitment is possible.Comment: 7 pages Latex; v2 has 8 pages and additional references and
clarifications, this paper is to appear in the New Journal of Physic
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