Results 21 to 30 of about 9,097,410 (138)

Entanglement Dissipation: Unitary and Non-unitary Processes [PDF]

, 2011
Dissipative processes in physics are usually associated with non-unitary actions. However, the important resource of entanglement is not invariant under general unitary transformations, and is thus susceptible to unitary "dissipation". In this note we discuss both unitary and non-unitary dissipative processes, showing that the former is ultimately of ...
arxiv   +1 more source

Two-party LOCC convertibility of quadpartite states and Kraus-Cirac number of two-qubit unitaries [PDF]

2014 J. Phys. A: Math. Theor. 47 424036, 2014
Nonlocal properties (globalness) of a non-separable unitary determine how the unitary affects the entanglement properties of a quantum state. We apply a given two-qubit unitary on a quadpartite system including two reference systems and analyze its "LOCC partial invertibility" under two-party LOCC. A decomposition given by Kraus and Cirac for two-qubit
arxiv   +1 more source

(t, n) Threshold Quantum State Sharing Scheme Based on Linear Equations and Unitary Operation

IEEE Photonics Journal, 2017
Quantum state sharing (QSTS) plays an important role in transporting, managing, and distributing keys. In this paper, by adopting the linear equation instead of using the Lagrange interpolation, a new idea of constructing (t, n) threshold quantum state ...
Cao Hao, Wenping Ma
semanticscholar   +1 more source

Ancilla-free certification of unitary quantum processes [PDF]

arXiv, 2022
We study efficient quantum certification algorithms for unitary quantum process using no ancilla. Previous study showed that one can distinguish whether an unknown unitary $U$ is equal to or $\varepsilon$-far from a known or unknown unitary $V$ in fixed dimension with $O(\varepsilon^{-2})$ uses of the unitary, in which the Choi state is used and thus a
arxiv  

The Unitary Transformation in Quantum Teleportation [PDF]

, 2006
In the well known treatment of quantum teleportation, the receiver should convert the state of his EPR particle into the replica of the unknown quantum state by one of four possible unitary transformations. However, the importance of these unitary transformations must be emphasized.
arxiv   +1 more source

Robust and parsimonious realisations of unitaries in the one-way model [PDF]

, 2004
We present a new set of generators for unitary maps over \otimes^n(C^2) which differs from the traditional rotation-based generating set in that it uses a single-parameter family of 1-qubit unitaries J(a), together with a single 2-qubit unitary controlled-Z. Each generator is implementable in the one-way model using only two qubits, and this leads to
arxiv   +1 more source

Interactive Proofs for Synthesizing Quantum States and Unitaries [PDF]

arXiv, 2021
Whereas quantum complexity theory has traditionally been concerned with problems arising from classical complexity theory (such as computing boolean functions), it also makes sense to study the complexity of inherently quantum operations such as constructing quantum states or performing unitary transformations. With this motivation, we define models of
arxiv  

Formation of Non-Unitary State near the Upper-Critical Field of Sr2RuO4 [PDF]

, 2005
We have studied the superconducting state of Sr 2 RuO 4 under a magnetic field parallel to the superconducting plane. We show that due to a weak spin–orbit coupling, a nonunitary \(k_{y}(\hat{\mathbf{z}}-\mathrm{i}\alpha\hat{\mathbf{y}})\) state is ...
M. Udagawa, Y. Yanase, M. Ogata
semanticscholar   +1 more source

Andreev reflection in unitary and non-unitary triplet states [PDF]

arXiv, 1997
The quasiparticle reflection and transmission properties at normal conductor-superconductor interfaces are discussed for unitary and non-unitary spin triplet pairing states recently proposed for Sr_2RuO_4. We find resonance peaks in the Andreev reflection amplitude, which are related to surface bound states in the superconductor.
arxiv  

Construction of Random Unitary Operations for Asymptotic Preparation of Werner States [PDF]

arXiv, 2019
Werner states are defined as bipartite qudit states that remain unchanged under application of arbitrary unitary operators acting on both subsystems simultaneously. Their preparation is a crucial ingredient in entanglement distillation protocols. This thesis deals with an iterative approach to prepare Werner states asymptotically, using random unitary ...
arxiv