Southwest Quantum Information and Technology

Quantum state transfer using input-output theory with time-reversal

Presenting Author: Kevin Randles, University of Oregon
Contributing Author(s): Steven van Enk

Achieving quantum state transfer between separate nodes of a quantum network is a topical problem in developing quantum computing and quantum communication systems. Input-output theory can be used to manage a wide class of field states driving cascaded quantum systems to achieve quantum state transfer. We show how the standard input-output theory is non-trivially modified if the photon is manipulated while propagating between two nodes, from system 1 to system 2. We present a unitary transformation, U, that time-reverses, frequency translates, and stretches the photon wave packet emitted by system 1. U can be tuned to match the different resonance frequencies and decay rates of the systems so that the wave packet is absorbed by system 2. We find that system 2 effectively responds to the time-reversed dynamics of system 1, which can be understood in terms of a change to the state's time argument, rho(t) = rho_1(t') tensor rho_2(t), where t' is a fictitious time for system 1 that runs backwards. For three-level Lambda-systems we numerically illustrate that performing a faultless unitary transformation results in ideal quantum state transfer and analyze the impact of imperfect transformations.

Read this article online: https://arxiv.org/abs/2204.11377

(Session 5 : Thursday from 5:00 pm - 7:00 pm)