The authors introduce a quantum nonlocal scheme for $n$ -particle systems using a theoretical model and a quantum simulation. They find a particular version of Hardy's paradox that yields a very high nonlocal probability that approaches 15.6% as the system size $n$ grows.The authors introduce a quantum nonlocal scheme for $n$-particle systems using a theoretical model and a quantum simulation. They find a particular version of Hardy's paradox that yields a very high nonlocal probability that approaches 15.6% as the system size $n$ grows.

arXiv:2209.05716Physical Review AApr 14, 202313 citations

Hardy-type paradoxes for an arbitrary symmetric bipartite Bell scenario

Kai-Siang Chen, Shiladitya Mal, Gelo Noel M. Tabia +1 more

As with a Bell inequality, Hardy's paradox manifests a contradiction between the prediction given by quantum theory and local hidden-variable theories. In this work, we give two generalizations of Hardy's arguments for manifesting such a paradox to an arbitrary, but symmetric, Bell scenario involving two observers. Our constructions recover that of Meng et al. [Phys. Rev. A 98, 062103 (2018)] and that first discussed by Cabello [Phys. Rev. A 65, 032108 (2002)] as special cases. Among the two constructions, one can be naturally interpreted as a demonstration of the failure of the transitivity of implications (FTI). Moreover, one of their special cases is equivalent to a ladder-proof-type argument for Hardy's paradox. Through a suitably generalized notion of success probability called degree of success, we provide evidence showing that the FTI-based formulation exhibits a higher degree of success compared with all other existing proposals. Moreover, this advantage seems to persist even if we allow imperfections in realizing the zero-probability constraints in such paradoxes. Explicit quantum strategies realizing several of these proofs of nonlocality without inequalities are provided.As with a Bell inequality, Hardy's paradox manifests a contradiction between the prediction given by quantum theory and local hidden-variable theories. In this work, we give two generalizations of Hardy's arguments for manifesting such a paradox to an arbitrary, but symmetric, Bell scenario involving two observers. Our constructions recover that of Meng et al. [Phys. Rev. A 98, 062103 (2018)] and that first discussed by Cabello [Phys. Rev. A 65, 032108 (2002)] as special cases. Among the two constructions, one can be naturally interpreted as a demonstration of the failure of the transitivity of implications (FTI). Moreover, one of their special cases is equivalent to a ladder-proof-type argument for Hardy's paradox. Through a suitably generalized notion of success probability called degree of success, we provide evidence showing that the FTI-based formulation exhibits a higher degree of success compared with all other existing proposals. Moreover, this advantage seems to persist even if we allow imperfections in realizing the zero-probability constraints in such paradoxes. Explicit quantum strategies realizing several of these proofs of nonlocality without inequalities are provided.

arXiv:2311.02045Physical Review AApr 8, 20242 citations

The Nature of Quantum Paradoxes

Van der Merwe, Alwyn, Gino Tarozzi

Springer eBooksJan 1, 19889 citations

Realigned Hardy’s paradox

Shuai Zhao, Qing Zhou, Si-Ran Zhao +7 more

Hardy’s paradox provides an “All-versus-Nothing” fashion to directly certify that quantum mechanics cannot be completely described by local realistic theory. However, when considering potential imperfections in experiments, like noisy entanglement source and low detection efficiency, the original Hardy’s paradox can only induce a rather small Hardy violation, and is difficult to reveal. To overcome this challenge, we have proposed a realigned Hardy’s paradox, which can dramatically improve the Hardy violation. Furthermore, we have generalized the realigned Hardy’s paradox to arbitrary even n dichotomic measurements. For n=2, 4 and 6 cases, the realigned Hardy’s paradox can achieve Hardy values approximate 0.4140, 0.7734 and 0.8875 respectively for qubit systems, compared with only 0.09 of the original Hardy’s paradox. Meanwhile, the structure of the realigned Hardy’s paradox is simpler and more robust, in the sense that there is only one Hardy condition. We anticipate that the realigned Hardy’s paradox can tolerate more experimental imperfections and help to stimulate more fascinating quantum information applications.Hardy’s paradox provides an “All-versus-Nothing” fashion to directly certify that quantum mechanics cannot be completely described by local realistic theory. However, when considering potential imperfections in experiments, like noisy entanglement source and low detection efficiency, the original Hardy’s paradox can only induce a rather small Hardy violation, and is difficult to reveal. To overcome this challenge, we have proposed a realigned Hardy’s paradox, which can dramatically improve the Hardy violation. Furthermore, we have generalized the realigned Hardy’s paradox to arbitrary even n dichotomic measurements. For n=2, 4 and 6 cases, the realigned Hardy’s paradox can achieve Hardy values approximate 0.4140, 0.7734 and 0.8875 respectively for qubit systems, compared with only 0.09 of the original Hardy’s paradox. Meanwhile, the structure of the realigned Hardy’s paradox is simpler and more robust, in the sense that there is only one Hardy condition. We anticipate that the realigned Hardy’s paradox can tolerate more experimental imperfections and help to stimulate more fascinating quantum information applications.

arXiv:2211.13642Results in PhysicsNov 23, 20230 citations

The authors introduce a quantum nonlocal scheme for

n

-particle systems using a theoretical model and a quantum simulation. They find a particular version of Hardy's paradox that yields a very high nonlocal probability that approaches 15.6% as the system size

n

grows.