Spin-photon entanglement and photonic cluster states generation with a semiconductor quantum dot in a cavity

Solid‐State Single‐Photon Sources: Recent Advances for Novel Quantum Materials

“…In addition to allowing unity B in principle, they also allow polarization to be used as a qubit degree of freedom that can be entangled with a degree of freedom of the emitter, such as the electron spin, provided that the emitter level structure allows for it. Such spinphoton entanglement can be exploited to deterministically generate more complicated multi-photon states such as linear cluster states [61,62] and Greenberger-Horne-Zeilinger (GHZ) states [63,64] (additionally, we note that GHZ states can be generated in integrated circuits via heralding, using bright solid-state singlephoton sources). [65][66][67]…”

“…The current state-of-the-art on cluster state generation based on spin-photon entanglement in QDs [62,64] has demonstrated a cluster state of up to 10 photons, [61] still behind the performance attainable with natural atoms ( 87 Rb) coupled to cavities. [120] A technological challenge that QD sources are facing is their performance in the generation of indistinguishable telecom single-photons (mostly due to the semiconductor growth complexity in this frequency range), crucial in fibercommunication.…”

“…Complete BPI benchmark III-V QDs Y [ 52] 84.5* 56 97.9 95.9 / ≈50 000 Y [ 61,62,64] Er ions Y [ 94] 72.1 3.5 98.2 80 / 19.4 Y TMD QDs Y [ 82] 65 [ 82] 2.4 [ 165] 96.4 [ 83] <2 / 7.4 [ 82] N hBN defects N 13 [ 234] 1.3 [ 234] 99.4 [ 244] 56 / 6.6 [ 245] Y [ 261,262] PQDs N N 1.1 [ 278] ≈98 [ 302] 56 / 7.9 [ 276] N coupled to cavities (emitting in the telecom range), [94] and finally the best individual BPI performances of the three emergent materials discussed in this review. It is worth remarking that among TMD QDs, hBN defects, and PQDs, only Ref.…”

Resonant two-laser spin-state spectroscopy of a negatively charged quantum dot-microcavity system with a cold permanent magnet

“…Magneto-optical quantum dot-based experiments usually rely on large and complex superconducting magnets [7,26], which generate strong magnetic fields but require both a stabilized current source and cryogenic temperatures. However, many experiments need only a "set-and-forget" static magnetic field of around 500 mT, which can be achieved with compact strong permanent magnets cooled down together with the quantum dot device [27][28][29].…”

“…An efficient, tunable spin-photon interface that allows high fidelity entanglement of spin qubits with flying qubits, photons, lies at the heart of many building blocks of distributed quantum technologies [1], ranging from quantum repeaters [2], photonic gates [3,4], to the generation of photonic cluster states [5][6][7]. Further, to secure connectivity within the quantum network, an ideal spin-photon interface requires near-unity collection efficiency, therefore an atom or semiconductor quantum dot (QD) carrying a single spin as a quantum memory is integrated into photonic structures such as optical microcavities cavities, where recently 57 % in-fiber photon collection efficiency has been achieved [8].…”