A family of loss-tolerant quantum coin flipping protocols

We present a family of loss-tolerant quantum strong coin flipping protocols; each protocol differing in the number of qubits employed. For a single qubit we obtain a bias of 0.4, reproducing the result of Berl\'{i}n et al. [Phys. Rev. A 80, 062321 (2009)], while for two qubits we obtain a bias of 0.3975. Numerical evidence based on semi-definite programming indicates that the bias continues to decrease as the number of qubits is increased but at a rapidly decreasing rate

On the relation between Bell inequalities and nonlocal games

We investigate the relation between Bell inequalities and nonlocal games by presenting a systematic method for their bilateral conversion. In particular, we show that while to any nonlocal game there naturally corresponds a unique Bell inequality, the converse is not true. As an illustration of the method we present a number of nonlocal games that admit better odds when played using quantum resourcesComment: v3 changes: Updates to reflect PLA version. 1 examples changed. Physics Letters A (accepted for publication

Quantum advantages in classically defined tasks

We analyze classically defined games for which a quantum team has an advantage over any classical team. The quantum team has a clear advantage in games in which the players of each team are separated in space and the quantum team can use unusually strong correlations of the Einstein-Podolsky-Rosen (EPR) type. We present an example of a classically defined game played at one location for which quantum players have a real advantage.Comment: 4 pages, revised version, to be published in PR

Cyclic angiotensin-(1-7) contributes to rehabilitation of animal performance in a rat model of cerebral stroke

Peptidase-resistant, lanthionine-stabilized angiotensin-(1-7), termed cAng-(1-7), has shown therapeutic efficacy in animal models of cardiovascular, metabolic, kidney and pulmonary disease. Goal of the present study was testing the capacity of subcutaneously administered cAng-(1-7) to induce rehabilitation of animal performance in the transient middle cerebral artery occlusion rat model of cerebral stroke. 24 h after ischemic stroke induction, cAng-(1-7) was administered for 28 days at a dose of 500 μg/kg/day, either daily via subcutaneous injection or continuously via an alzet pump. Both ways of administration of cAng-(1-7) were equally effective. Measurements were continued until day 50. Compared to vehicle, cAng-(1-7) clearly demonstrated significantly increased capillary density (p < 0.01) in the affected hemisphere and improved motor and somatosensory functioning. The modified neurological severity score (p < 0.001 at days 15 and 50), stepping test (p < 0.001 at days 36–50), forelimb placement test (p < 0.001 at day 50), body swing test (p < 0.001 at days 43 and 50) all demonstrated that cAng-(1-7) caused significantly improved animal performance. Taken together the data convincingly indicate rehabilitating capacity of subcutaneously injected cAng-(1-7) in cerebral ischemic stroke

Continuous input nonlocal games

We present a family of nonlocal games in which the inputs the players receive are continuous. We study three representative members of the family. For the first two a team sharing quantum correlations (entanglement) has an advantage over any team restricted to classical correlations. We conjecture that this is true for the third member of the family as well.Comment: Journal version, slight modification

Coronary sinus ostial occlusion during retrograde delivery of cardioplegic solution significantly improves cardioplegic distribution and efficacy

AbstractThis study documents the gross flow characteristics and capillary distribution of cardioplegic solution delivered retrogradely with the coronary sinus open versus closed. Methods : Five explanted human hearts from transplant recipients were used as experimental models. Hearts served as their own controls and received two doses of warm blood cardioplegic solution, each containing colored microspheres. The first dose was delivered through a retroperfusion catheter with the coronary sinus open and the second dose was delivered with the sinus occluded. Capillary flow was measured at twelve ventricular sites and gross flow was measured by examining coronary sinus regurgitation, thebesian vein drainage, and aortic effluent (nutrient flow). Results : Coronary sinus ostial occlusion allowed for a significant decrease in total cardioplegic flow (1.74 ± 0.40 ml/gm versus 1.06 ± 0.32 ml/gm; p < 0.05) to occur while maintaining an identical intracoronary sinus pressure. Ostial occlusion also resulted in an increase in the ratio of nutrient flow/total cardioplegic flow from 32.3% ± 15.1% to 61.3% ± 7.9% (p < 0.05). A statistically significant improvement in capillary flow was found at the midventricular level in the posterior intraventricular septum and posterolateral right ventricular free wall. This improvement was also documented for the intraventricular septum and right ventricle at the level of the apex. Conclusion : Coronary sinus occlusion during retrograde cardioplegia significantly improves cardioplegic delivery to the right ventricle and posterior intraventricular septum. Furthermore, the technique affords a significant improvement in nutrient cardioplegic flow while reducing the overall volume of cardioplegic solution administered. ( J T HORAC C ARDIOVASC S URG 1995; 109: 941-7

Flipping quantum coins

Coin flipping is a cryptographic primitive in which two distrustful parties wish to generate a random bit in order to choose between two alternatives. This task is impossible to realize when it relies solely on the asynchronous exchange of classical bits: one dishonest player has complete control over the final outcome. It is only when coin flipping is supplemented with quantum communication that this problem can be alleviated, although partial bias remains. Unfortunately, practical systems are subject to loss of quantum data, which restores complete or nearly complete bias in previous protocols. We report herein on the first implementation of a quantum coin-flipping protocol that is impervious to loss. Moreover, in the presence of unavoidable experimental noise, we propose to use this protocol sequentially to implement many coin flips, which guarantees that a cheater unwillingly reveals asymptotically, through an increased error rate, how many outcomes have been fixed. Hence, we demonstrate for the first time the possibility of flipping coins in a realistic setting. Flipping quantum coins thereby joins quantum key distribution as one of the few currently practical applications of quantum communication. We anticipate our findings to be useful for various cryptographic protocols and other applications, such as an online casino, in which a possibly unlimited number of coin flips has to be performed and where each player is free to decide at any time whether to continue playing or not.Comment: 17 pages, 3 figure