Optical Fiber Communication Conference

Requirement of optical coherence for continuous-variable quantum teleporation

Terry Rudolph, Barry C. Sanders

Published Jan 1, 2001• 0 citations

Abstract

We show that unconditional quantum teleportation of continuous variables requires coherent devices for the sender (Alice) and the receiver (Bob) and that this requirement is not in principle achievable in experiments employing conventional laser sources.

DOI: 10.1364/icqi.2001.pa9

Related papers

Requirement of Optical Coherence for Continuous-Variable Quantum Teleportation

Terry Rudolph, Barry C. Sanders

We show that the sender and the receiver each require coherent devices in order to achieve unconditional continuous variable quantum teleportation (CVQT), and this requirement cannot be achieved with conventional laser sources, linear optics, ideal photon detectors, and perfect Fock state sources. The appearance of successful CVQT in recent experiments is due to interpreting the measurement record fallaciously in terms of one preferred ensemble (or decomposition) of the correct density matrix describing the state. Our analysis is unrelated to technical problems such as laser phase drift or finite squeezing bandwidth.

arXiv:quant-ph/0103147Physical Review LettersJul 31, 200180 citations

Continuous variable teleportation requires optical coherence

Terry Rudolph, Barry C. Sanders

Summary form only given. Quantum teleportation, first proposed as a method for teleporting an unknown spin-1/2 quantum state from a sender, "Alice", to a receiver, "Bob", has been extended to continuous-variable quantum teleportation (CVQT). In this variant of quantum teleportation, Bob and Alice share a nonlocal entangled two-mode field which, ideally, should have perfect correlations between in-phase quadrature ('position' x) and out-of-phase quadrature ('momentum' p), although the requirement of perfect correlations can be relaxed somewhat. The experimental success of CVQT has recently been reported, with two-mode squeezed light providing the nonlocal, entangled source shared between Alice and Bob. The objective here is to consider whether CVQT has indeed been achieved, or could ever be achieved, in optical experiments employing conventional laser sources. In particular we show that, in the context of this experiment, Alice and Bob may not employ independent laser sources for their operations if the state is to be teleported, yet this requires them to share more than just the Einstein-Podolsky-Rosen (EPR) resource.

Quantum Electronics and Laser Science ConferenceNov 13, 20020 citations

Comment: There is no unmet requirement of optical coherence for continuous-variable quantum teleportation

Howard M. Wiseman

It has been argued that continuous-variable quantum teleportation at optical frequencies has not been achieved because the source used (a laser) was not ‘truly coherent’. Here it is shown that ‘true coherence’ is always illusory, as the concept of absolute time on a scale beyond direct human experience is meaningless. A laser is as good a clock as any other, even in principle, and this objection to teleportation experiments is baseless.

arXiv:quant-ph/0209163Journal of Modern OpticsJul 1, 20038 citations

There is no unmet requirement of optical coherence for continuous-variable quantum teleportation

Howard M. Wiseman

It has been argued [T.Rudolph and B.C. Sanders, Phys.Rev. Lett.87, 077903 (2001)] that continuous-variable quantum teleportation at optical frequencies has not been achieved because the source used (a laser) was not 'truly coherent'.Here I show that 'true coherence' is always illusory, as the concept of absolute time on a scale beyond direct human experience is meaningless.A laser is as good a clock as any other, even in principle, and this objection to teleportation experiments is baseless.

Journal of Modern OpticsJan 1, 20032 citations

Teleportation

Yorick Hardy, Willi-Hans Steeb

Quantum teleportation is the disembodied transport of an unknown quantum state |ψ〉 from one place to another. All protocols for accomplishing such transport require nonlocal correlations, or entanglement, between systems shared by sender and receiver. The sender is normally called Alice and the receiver is called Bob . Most attention has focused on teleporting the states of finite-dimensional systems, such as the two-dimensional polarization of a photon or the discrete level structure of an atom. First proposed in 1993 by Charles Bennett and his colleagues [17, 24, 138] quantum teleporation thus allows physicists to take a photon or any other quantum scale particle such as an atom and transfer its properties (such as the polarization) to another photon even if the two photons are on opposite sides of the galaxy. This scheme transports the particle’s properties to the remote location and not the particle itself. The state of the original particle must be destroyed to create an exact reconstruction at the other end. This is a consequence of the no cloning theorem. A role in the teleportation scheme is played by an entangled ancillary pair of particles which will be initially shared by Alice and Bob.

Birkhäuser Basel eBooksJan 1, 20010 citations

Asymmetric Bidirectional Quantum Teleportation employing hexa-modal Entangled Coherent States as the Quantum Channel

Ankita Pathak, Nidhi Singh, Nikhita Singh +1 more

A Bidirectional Quantum Teleportation protocol between two parties (Alice and Bob) is investigated in which Alice possesses arbitrary entangled coherent state and Bob preserve unknown superposed coherent state via a quantum channel (hexa- modal entangled coherent states). This assymeteric bidirectional protocol is worked out in continuous variable (coherent states) regime.

Aug 28, 20231 citation