Related papers: Transfer of Spatial Reference Frame Using Singlet …
We show that a Shared Singlet State (SSS) can supersede a Shared Reference Frame (SRF) in certain quantum communication tasks, i.e. tasks in which two remote players are required to estimate certain parameters of a two particle state sent…
A quantum key distribution protocol with classical Bob based on polarization entangled photon pairs is presented. It approximates a single photon and exploited the inherent randomness of quantum measurements to attain highly secure keys and…
Let Alice and Bob be able to make local quantum measurements and communicate classically. The set of mathematically consistent joint probability assignments (``states'') for such measurements is properly larger than the set of…
We consider the scenario in which Alice transmits private classical messages to Bob via a classical-quantum channel, part of whose output is intercepted by an eavesdropper, Eve. We prove the existence of a universal coding scheme under…
We consider an unknown quantum state shared between two parties, Alice and Bob, and ask how much quantum communication is needed to transfer the full state to Bob. This problem is known as state merging and was introduced in [Horodecki et…
We consider the problem of bi-directional controlled quantum teleportation of information encoded in phase opposite coherent state among two distant partners Alice and Bob, with the consent of controller, Charlie. We use five-mode…
In the standard protocol for quantum teleportation, one assumes that Bob is able to perform ideal operations on his qubit. Here, we analyze the case in which some of these operations are more reliable than others. Moreover, we consider the…
In 1-out-of-2 oblivious transfer (OT), Alice inputs numbers x_0, x_1, Bob inputs a bit b and outputs x_b. Secure OT requires that Alice and Bob learn nothing about b and x_{\bar{b}}, respectively. We define spacetime-constrained oblivious…
I propose to replace the dual classical and nonlocal channels used for teleporting unknown quantum states in the original protocol (OP) [Bennett, C. H., et al. Phys. Rev. Lett. 70 1895 (1993)] by either (i) one single quantum channel or…
Bell's theorem states that quantum mechanics is not a locally causal theory. This state is often interpreted as nonlocality in quantum mechanics. Toner and Bacon [Phys. Rev. Lett. \textbf{91}, 187904 (2003)] have shown that a shared…
We consider the scenario where Alice wants to send a secret (classical) $n$-bit message to Bob using a classical key, and where only one-way transmission from Alice to Bob is possible. In this case, quantum communication cannot help to…
A quantum interface for two-way entanglement transfer between orbital angular momentum degree of freedom in free space and time-energy degree of freedom in optical fibers, provides a novel way toward establishing entanglement between remote…
Alice can distribute a quantum state $|\phi>$ to $N$ spatially separated parties(say Bobs) by telecloning. It is possible for Charlie to reconstruct the quantum state to him if he shares same kind of telecloning quantum channel with Bobs…
We develop a quantum teleportation protocol of an unknown optical single rail qubit using a hybrid quantum channel composed of continuous variable (CV) states of certain parity. The quantum channel is characterized by two parameters: a…
We illustrate using a quantum system the principle of a cryptographic switch, in which a third party (Charlie) can control to a continuously varying degree the amount of information the receiver (Bob) receives, after the sender (Alice) has…
A theoretical scheme for controlled and secure direct communication is proposed. The communication is based on GHZ state and controlled quantum teleportation. After insuring the security of the quantum channel (a set of qubits in the GHZ…
In this paper we propose a method through which $n$-qubit states can simultaneously be bi-directionally transmitted between two users. We assume that Alice and Bob, the legitimate users, each have a $n$-qubit GHZ-like state and want to…
We have devised an optical scheme for the recently proposed protocol for encoding two qubits into one qutrit. In this protocol, Alice encodes an arbitrary pure product state of two qubits into a state of one qutrit. Bob can then restore…
Quantum teleportation, the process by which Alice can transfer an unknown quantum state to Bob by using pre-shared entanglement and classical communication, is one of the cornerstones of quantum information. The standard benchmark for…
We presen a secure direct communication protocol by using step-split Einstein-Podolsky-Rosen (EPR) pair. In this communication protocol, Alice first sends one qubit of an EPR pair to Bob. Bob sends a receipt signal to Alice through public…