91 research outputs found
Energy efficient mining on a quantum-enabled blockchain using light
We outline a quantum-enabled blockchain architecture based on a consortium of
quantum servers. The network is hybridised, utilising digital systems for
sharing and processing classical information combined with a fibre--optic
infrastructure and quantum devices for transmitting and processing quantum
information. We deliver an energy efficient interactive mining protocol enacted
between clients and servers which uses quantum information encoded in light and
removes the need for trust in network infrastructure. Instead, clients on the
network need only trust the transparent network code, and that their devices
adhere to the rules of quantum physics. To demonstrate the energy efficiency of
the mining protocol, we elaborate upon the results of two previous experiments
(one performed over 1km of optical fibre) as applied to this work. Finally, we
address some key vulnerabilities, explore open questions, and observe
forward--compatibility with the quantum internet and quantum computing
technologies.Comment: 25 pages, 5 figure
Experimental semi-device-independent certification of entangled measurements
Certifying the entanglement of quantum states with Bell inequalities allows
one to guarantee the security of quantum information protocols independently of
imperfections in the measuring devices. Here we present a similar procedure for
witnessing entangled measurements, which play a central role in many quantum
information tasks. Our procedure is termed semi-device-independent, as it uses
uncharacterized quantum preparations of fixed Hilbert space dimension. Using a
photonic setup, we experimentally certify an entangled measurement using
measurement statistics only. We also apply our techniques to certify
unentangled but nevertheless inherently quantum measurements.Comment: 7 pages, 2 figure
Experimental measurement-device-independent verification of quantum steering
Bell non-locality between distant quantum systems-that is, joint correlations which violate a Bell inequality-can be verified without trusting the measurement devices used, nor those performing the measurements. This leads to unconditionally secure protocols for quantum information tasks such as cryptographic key distribution. However, complete verification of Bell non-locality requires high detection efficiencies, and is not robust to typical transmission losses over long distances. In contrast, quantum or Einstein-Podolsky-Rosen steering, a weaker form of quantum correlation, can be verified for arbitrarily low detection efficiencies and high losses. The cost is that current steering-verification protocols require complete trust in one of the measurement devices and its operator, allowing only one-sided secure key distribution. Here we present measurement-device-independent steering protocols that remove this need for trust, even when Bell non-locality is not present. We experimentally demonstrate this principle for singlet states and states that do not violate a Bell inequality.Australian Research Council/140100648Marie-Curie Fellowshi
A detailed analysis of the effects of methamphetamine on schedule-controlled responding in pigeons
In behavioral pharmacology, overall response rate is the measure most often used to
study the effects of drugs on an animal’s ongoing operant behavior. However, it has been argued
that an overall measure of response rate may not provide the most valid description of behavior
and, thus, a more detailed analysis might prove beneficial in classifying drug effects. The
purpose of the present research was to (1) study effects of methamphetamine on schedulecontrolled
responding, (2) determine if a log-survivor analysis recently used to study nose-poke
responding in rats could be extended for use with key-pecking in pigeons and (3) examine
microproperties of pigeon responding using an IRT analysis. Pigeons were trained to peck a
lighted key under a multiple random-interval (RI) 1-min, RI 4-min schedule. Interresponse times
(IRTs) were collected and then analyzed via log-survivor plots and an analysis described by
Blough (1963) and used in greater detail by Palya (1992). Log-survivor plots show the
proportion of IRTs greater than some time as a function of time in the session. The IRT analysis
involved graphing each individual IRT as a function of its temporal position within the interval.
Several doses of methamphetamine were administered (0.3 – 5.6 mg/kg) and the effect on both
summary measures (overall response rates) as well as the more detailed analyses was observed.
Log-survivor analyses did not produce the “broken-stick” responding seen in previous studies
with rats and quantitative measures of bout-initiations and within-bout responses could not be
obtained. The IRT plots showed clear bands of responding at 350 ms and 700 ms and responding
in the initial (350 ms) band was affected more than responding during other bands or at other
IRTs. These results strengthen the argument that not all responding (various IRTs) is uniformly
affected by methamphetamine administration and suggest that a detailed analysis of responding
might prove more useful than summary measures in characterizing drug effects on behavior
Non-Minimal Coupling to a Lorentz-Violating Background and Topological Implications
The non-minimal coupling of fermions to a background responsible for the
breaking of Lorentz symmetry is introduced in Dirac's equation; the
non-relativistic regime is contemplated, and the Pauli's equation is used to
show how an Aharonov-Casher phase may appear as a natural consequence of the
Lorentz violation, once the particle is placed in a region where there is an
electric field. Different ways of implementing the Lorentz breaking are
presented and, in each case, we show how to relate the Aharonov-Casher phase to
the particular components of the background vector or tensor that realises the
violation of Lorentz symmetry.Comment: 8 pages, added references, no figure
Strict Selection Alone of Patients Undergoing Liver Transplantation for Hilar Cholangiocarcinoma Is Associated with Improved Survival
Liver transplantation for hilar cholangiocarcinoma (hCCA) has regained
attention since the Mayo Clinic reported their favorable results with the use
of a neo-adjuvant chemoradiation protocol. However, debate remains whether the
success of the protocol should be attributed to the neo-adjuvant therapy or to
the strict selection criteria that are being applied. The aim of this study
was to investigate the value of patient selection alone on the outcome of
liver transplantation for hCCA. In this retrospective study, patients that
were transplanted for hCCA between1990 and 2010 in Europe were identified
using the European Liver Transplant Registry (ELTR). Twenty-one centers
reported 173 patients (69%) of a total of 249 patients in the ELTR. Twenty-six
patients were wrongly coded, resulting in a study group of 147 patients. We
identified 28 patients (19%) who met the strict selection criteria of the Mayo
Clinic protocol, but had not undergone neo-adjuvant chemoradiation therapy.
Five–year survival in this subgroup was 59%, which is comparable to patients
with pretreatment pathological confirmed hCCA that were transplanted after
completion of the chemoradiation protocol at the Mayo Clinic. In conclusion,
although the results should be cautiously interpreted, this study suggests
that with strict selection alone, improved survival after transplantation can
be achieved, approaching the Mayo Clinic experience
Strict Selection Alone of Patients Undergoing Liver Transplantation for Hilar Cholangiocarcinoma is Associated with Improved Survival
Liver transplantation for hilar cholangiocarcinoma (hCCA) has regained attention since the Mayo Clinic reported their favorable results with the use of a neo-adjuvant chemoradiation protocol. However, debate remains whether the success of the protocol should be attributed to the neo-adjuvant therapy or to the strict selection criteria that are being applied. The aim of this study was to investigate the value of patient selection alone on the outcome of liver transplantation for hCCA. In this retrospective study, patients that were transplanted for hCCA between 1990 and 2010 in Europe were identified using the European Liver Transplant Registry (ELTR). Twenty-one centers reported 173 patients (69%) of a total of 249 patients in the ELTR. Twenty-six patients were wrongly coded, resulting in a study group of 147 patients. We identified 28 patients (19%) who met the strict selection criteria of the Mayo Clinic protocol, but had not undergone neo-adjuvant chemoradiation therapy. Five-year survival in this subgroup was 59%, which is comparable to patients with pretreatment pathological confirmed hCCA that were transplanted after completion of the chemoradiation protocol at the Mayo Clinic. In conclusion, although the results should be cautiously interpreted, this study suggests that with strict selection alone, improved survival after transplantation can be achieved, approaching the Mayo Clinic experience
- …