It is found that programmable parameters obey the standard quantum limit strictly; hence, no speedup is possible in its estimation and a class of nonunitary quantum channels is constructed whose parameter can be estimated in a way that thestandard quantum limit is broken.Expand

This work considers the quantum interactiveProof system model of computation, which is the (classical) interactive proof system model’s natural quantum computational analogue, and concludes that quantum computing provides no increase in computational power whatsoever over classical computing in the context of interactive proof systems.Expand

This work gives a theoretical measurement scheme (POVM) that requires copies to achieve error, and proves that for independent (product) measurements, it can be implemented on a quantum computer in time polynomial.Expand

This work proves that every problem in the complexity class QMA has a quantum interactive proof system that is zero-knowledge with respect to efficient quantum computations.Expand

Pseudorandom quantum states, which appear random to any quantum polynomial-time adversary, are proposed, which offers a computational approximation to perfectly random quantum states analogous in spirit to cryptographic pseudorandom generators.Expand

This work makes an interesting connection between the theory of QMA-completeness and Hamiltonian complexity on one hand and the study of non-local games and Bell inequalities on the other.Expand

This paper shows that several concepts including the quantum chromatic number and the Kochen-Specker sets that arose from different contexts fit naturally in the binary constraint system framework, and provides a simple parity constraint game that requires $\Omega(\sqrt{n})$ EPR pairs in perfect strategies.Expand

It is proved that every problem that is recursively enumerable, including the Halting problem, can be efficiently verified by a classical probabilistic polynomial-time verifier interacting with two all-powerful but noncommunicating provers sharing entanglement.Expand

We introduce an algebra qCCS of pure quantum processes in which communications by moving quantum states physically are allowed and computations are modeled by super-operators, but no classical data… Expand

A remarkable consequence of these results is that certain multipartite transformations, impossible even probabilistically, can become possible when performed in multiple-copy bunches or when assisted by some catalyzing state.Expand