Single-photon Mach–Zehnder interferometer for quantum networks based on the single-photon Faraday effect

Abstract

Articles you may be interested inSingle-mode quantum cascade lasers employing asymmetric Mach-Zehnder interferometer type cavities Combining the recent progress in semiconductor nanostructures along with the versatility of photonic crystals in confining and manipulating light, quantum networks allow for the prospect of an integrated and low power quantum technology. Within quantum networks, which consist of a system of waveguides and nanocavities with embedded quantum dots, it has been demonstrated in theory that many-qubit states stored in electron spins could be teleported from one quantum dot to another via a single photon using the single-photon Faraday effect. However, in addition to being able to transfer quantum information from one location to another, quantum networks need added functionality such as ͑1͒ controlling the flow of the quantum information and ͑2͒ performing specific operations on qubits that can be easily integrated. In this paper, we show how a single-photon Mach-Zehnder interferometer ͑SMZI͒, that uses the concept of the single-photon Faraday effect to manipulate the polarization of a single photon, can be operated both as a switch to control the flow of quantum information inside the quantum network and as various single-qubit quantum gates to perform operations on a single photon. Given that the X gate, the Z gate, and the XZ gate are essential for the implementation of quantum teleportation, we show explicitly their implementation by means of our proposed SMZI. We also present the implementation of the Hadamard gate and the single-qubit phase gate, which are needed to complete the universal set of quantum gates for integrated quantum computing in a quantum network. Finally, the expected fidelity and robustness of the proposed SMZI are quantitatively explored by considering the phase errors within the SMZI.

Semiconductor spin noise spectroscopy: Fundamentals, accomplishments, and challenges

“…Especially, an implementation based on optical detection via Faraday rotation-as in SNS-is desirable since such a measurement is employed as building block in several schemes for photon-spin and spin-spin entanglement (see, e.g., Refs. [83,84,85,86,87,88]). …”

“…Besides possessing very sharp resonances, easy tunable optical density, and a longer spin lifetime, metal atoms in a vapor gas cell also carry the advantage of an easy optical access from all three spatial directions. Anyhow, in consideration of the experimental results that are reviewed in this section, it is surprising that in theoretical proposals of light and semiconductor spin entanglement [83,84,85,86,87,88], mostly single spins and not ensemble spins are considered. Additionally, isotropic exchange interaction in an electronic spin ensemble in a semiconductor [89] and the resulting correlated spin relaxation may allow for measurement precision beyond the standard quantum limit for timescales longer than the spin relaxation time [90].…”

Ultrafast optical switching in Kerr nonlinear photonic crystals

“…Because of the optical interference process of two beams in the Mach-Zehnder interferometer, the output intensity will be very sensitive to small change of phase caused by nonlinearity. By optimization of several geometrical parameters including the lengths of each arm, the lattice, and the radius of air holes, all-optical switching with low pump power can be realized [146]. Notice that this device does not involve significant local field enhancement.…”

A Mach-Zehnder Interferometry Method for the Measurement of Photonic State Squeezing in Quantum Cavities

“…A winner of the Nobel Prize, Serge Haroche, has presented an interesting non-demolition method for measuring Wigner function in a quantum cavity [12]. On the other hand, the Mach-Zehnder interferometry is applied to Bell's inequality [22,23], electronic Mach-Zehnder interferometer (MZI) [24], single and two photon interferometry [25,26], production and observation of Greenberger-Horne-Zeilinger entanglement [27], and optical amplification [28,29].…”