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arXiv:1404.0185

An On-Demand Single-Electron Time-Bin Qubit Source

J. R. Ott, Michael V. Moskalets

Published Apr 1, 2014• 0 citations
arXivHTMLPDF

Abstract

We propose a source capable of on-demand emission of single electrons with a wave packet of controllable shape and phase. The source consists of a hybrid quantum system, relying on currently experimentally accessible components. We analyze in detail the emission of single electron time-bin qubits, which we characterize using the well known electronic Hong-Ou-Mandel (HOM) interferometry scheme. Specifically, we show that, by controlling the phase difference of two time-bin qubits, the Pauli peak, the electronic analogue of the well known optical HOM dip, can be continuously removed. The proposed source constitutes a promising approach for scalable solid-state architectures for quantum operations using electrons and possibly for an interface for photon to electron time-bin qubit conversion.

DOI
10.48550/arxiv.1404.0185

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Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)•Jun 1, 2017•1 citation
We propose a source capable of on-demand emission of single electrons with a wave packet of controllable shape and phase. The source consists of a hybrid quantum system, relying on currently experimentally accessible components. We analyze in detail the emission of single electron time-bin qubits, which we characterize using the well known electronic Hong-Ou-Mandel (HOM) interferometry scheme. Specifically, we show that, by controlling the phase difference of two time-bin qubits, the Pauli peak, the electronic analogue of the well known optical HOM dip, can be continuously removed. The proposed source constitutes a promising approach for scalable solid-state architectures for quantum operations using electrons and possibly for an interface for photon to electron time-bin qubit conversion.
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A time-bin qubit is a promising candidate qubit for advanced quantum information processing systems operating over optical fibers or integrated quantum photonic circuits. However, the single- and two-qubit operations of time-bin qubits have been largely unexplored compared with those of polarization qubits. Here, I present a simple scheme for implementing a basic two-qubit operation, namely an ``entangling'' operation of two independent time-bin qubits, based on Hong-Ou-Mandel quantum interference in a high-speed $2\ifmmode\times\else\texttimes\fi{}2$ optical switch. With the proposed scheme, the formation of a time-bin entanglement was confirmed experimentally.
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Summary form only given. Hybrid quantum technologies seek to combine the advantages of two individual quantum architectures by transferring the information between the two systems. We want to benefit from the high mobility and ease of transmission of photons for quantum communication and exploit the excellent readout and storage capabilities of atomic qubits as a quantum memory, which is essential to build up quantum repeater networks for quantum data processing. Efficient interaction of photons with atoms requires a match of the photons spectral properties to those of the resonances of the atomic species. The atomic transition usually has a much narrower bandwidth than single photons generated by spontaneous parametric down-conversion (SPDC), the current gold standard of producing high-purity heralded single photons at flexible wavelengths. To develop hybrid quantum technologies therefore requires significantly reducing the single photon emission spectra to fulfill these requirements. The way we try to achieve this is by using an optical cavity to enhance the probability of creating the photons in the spectral and spatial resonator mode.We report 100% duty cycle generation of sub-MHz single photon pairs at the Rubidium D1 line using cavityenhanced spontaneous parametric down-conversion [3]. The double exponential decay of the temporal intensity cross-correlation function exhibits a bandwidth of 666 ± 16 kHz for the single photons, an order of magnitude below the natural linewidth of the target transition. This is, to our knowledge, the narrowest bandwidth of single photons from SPDC to date. A new method of placing a half-wave plate inside the cavity helps to achieve triple resonance between pump, signal and idler photon, reducing the bandwidth and simplifying the locking scheme. Additionally, stabilisation of the cavity to the pump frequency enables the 100% duty cycle. The quantum nature of the source is confirmed by the idler-triggered second-order autocorrelation function at τ = 0 to be g(2) s,s (0) = 0.016 ± 0.002 for a heralding rate of 5 kHz and antibunching below 0.5 is observed up to heralding rates of 250 kHz [3]. The high purity of the source is matched by high indistinguishability of the photons demonstrated in a Hong-Ou-Mandel (HOM) interference experiment with a visibility V = 96.5 ± 0.5 %. Additionally, the modelocked two-photon state of the generated pairs leads to revivals of the HOM dip. We observe these revivals up to 100 m path difference between signal and idler photon, independently proofing the long coherence length of our photons.