Programme

I.6 -- Invited, VCTP-44

Date: Tuesday, 30 July 2019

Time: 10:30 - 11:00

Joint Remote Preparation of General Quantum States of Arbitrary Dimensions

Nguyen Ba An (1,2)

(1) Thang Long Institute of Mathematics and Applied Sciences, Thang Long University; (2) Institute of Physics, Vietnam Academy of Science and Technology

Information can be encoded in quantum states. Secure and intact transfer of quantum information between distant nodes of a global quantum network is a demanding task for quantum communication and distributed quantum computation. Thanks to weird quantum entanglement, such task can be done only by means of local operations and classical messages, i.e., quantum information is transferable even though the state itself is not actually transported. Most famous is the protocol called quantum teleportation [1] which requires (a) physical supply of the state and (b) ability of performing Bell-state measurement. Later, a different protocol called remote state preparation (RSP) [2] was proposed that is free from the two requirements (a) and (b). However, RSP suffers from two drawbacks: (i) failure with a probability of 50% and (ii) leakage of full information to the preparer. Recently, a new protocol called joint remote state preparation (JRSP) [3] was put forward to get rid of all the above-mentioned weak points (a), (b), (i) and (ii). JRSP of arbitrary quDit states of dimensions D = 2, 4 and 8 was studied intensively using standard procedures. JRSP of equatorial single-quDit states as well as equatorial hybrid quDit-quNit entanglements of any dimensions have also been investigated. Nevertheless, JRSP of the most general quDit and quDit-quNit states turns out impposible by standard techniques. In this talk we propose nonstandard protocols using positive operator-valued measurements (POVMs), which are suitably designed so that our protocols work deterministically for arbitrary dimensions D and N. Furthermore, we also construct quantum circuits to realize the concerned POVMs [4]. The obtained results might be of interest from both theoretical and experimental point of view.
[1] C.H. Bennett et al., Phys. Rev. Lett. 70, 1895 (1993)
[2] See, e.g., A.K. Pati, Phys. Rev. A 63, 014302 (2000)
[3] N.B. An, J. Kim, J. Phys. B: At. Mol. Opt. Phys. 41, 095501 (2008)
[4] N.B. An, L.T. Dat, J. Kim, Phys. Rev. A 98, 042329 (2018)

Presenter: Nguyen Ba An