Creation and control of entanglement by time-delayed quantum-coherent feedback

Sven M. Hein; Alexander Carmele; Andreas Knorr

doi:10.1117/12.2207671

4 March 2016 Creation and control of entanglement by time-delayed quantum-coherent feedback

Sven M. Hein, Alexander Carmele, Andreas Knorr

Proceedings Volume 9742, Physics and Simulation of Optoelectronic Devices XXIV; 97420X (2016) https://doi.org/10.1117/12.2207671
Event: SPIE OPTO, 2016, San Francisco, California, United States

Abstract

Quantum information science relies on the feature of distant quantum entities (mostly "qubits") to form non-local states. A main challenge consists of generating such non-local entangled states between qubits. We exploit the fact that for coupled qubits, the eigenstates of the coupled system are usually highly entangled, and of different excitation energies. This allows to address the different entangled eigenstates by frequency-dependent control schemes.

In our proposal, we present such a control mechanism, and demonstrate how it can be used to create entanglement from a fully separable initial state. The mechanism of our choice is time-delayed quantum-coherent feedback. If a qubit occupation decays via the emission of a photon, one can store this photon for a delay time τ and couple the radiation back into the qubit afterwards. Through the choice of τ, one can set the phase of the feedback, which will then lead to either an increased or decreased qubit decay. Since this phase depends on sin(ωτ), this effect strongly depends on the qubit frequency ω. In particular, it can be used to separate different entangled states in a quantum network by enhancing the decay of all entangled eigenstates except one.

We discuss this protocol on the example of two coupled qubits, and analyze in detail its effectiveness depending on the feedback delay time τ.

Citation Download Citation

Sven M. Hein, Alexander Carmele, and Andreas Knorr "Creation and control of entanglement by time-delayed quantum-coherent feedback", Proc. SPIE 9742, Physics and Simulation of Optoelectronic Devices XXIV, 97420X (4 March 2016); https://doi.org/10.1117/12.2207671

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available