We analyze the entanglement properties of deterministic path-entangled photonic states generated by coupling the emission of a quantum-dot biexciton cascade to a chiral nanophotonic waveguide, as implemented by \O{}stfeldt et al. [PRX Quantum 3, 020363 (2022)]. We model the degree of entanglement through the concurrence of the two-photon entangled state in the presence of realistic experimental imperfections. The model accounts for imperfect chiral emitter-photon interactions in the waveguide and the asymmetric coupling of the exciton levels introduced by fine-structure splitting along with time jitter in the detection of photons. The analysis shows that the approach offers a promising platform for deterministically generating entanglement in integrated nanophotonic systems in the presence of realistic experimental imperfections.We analyze the entanglement properties of deterministic path-entangled photonic states generated by coupling the emission of a quantum-dot biexciton cascade to a chiral nanophotonic waveguide, as implemented by \O{}stfeldt et al. [PRX Quantum 3, 020363 (2022)]. We model the degree of entanglement through the concurrence of the two-photon entangled state in the presence of realistic experimental imperfections. The model accounts for imperfect chiral emitter-photon interactions in the waveguide and the asymmetric coupling of the exciton levels introduced by fine-structure splitting along with time jitter in the detection of photons. The analysis shows that the approach offers a promising platform for deterministically generating entanglement in integrated nanophotonic systems in the presence of realistic experimental imperfections.

arXiv:2301.04444Physical Review AJul 17, 20232 citations

Herzberg circuit and Berry's phase in chirality-based coded qubit in a triangular triple quantum dot

Chang‐Yu Hsieh, Alexandre René, Paweł Hawrylak

We present a theoretical proposal for the Herzberg circuit and controlled accumulation of Berry's phase in a chirality-based coded qubit in a triangular triple quantum dot molecule with one electron each. The qubit is encoded in the two degenerate states of a three-spin complex with total spin $S=1/2$ . Using a Hubbard and Heisenberg model the Herzberg circuit encircling the degeneracy point is realized by adiabatically tuning the successive on-site energies of quantum dots and tunnel couplings across a pair of neighboring dots. It is explicitly shown that encircling the degeneracy point leads to the accumulation of the geometrical Berry's phase. We show that only the triangular, not the linear, quantum dot molecule allows for the generation of Berry's phase and we discuss a protocol to detect this geometrical phase.We present a theoretical proposal for the Herzberg circuit and controlled accumulation of Berry's phase in a chirality-based coded qubit in a triangular triple quantum dot molecule with one electron each. The qubit is encoded in the two degenerate states of a three-spin complex with total spin $S=1/2$. Using a Hubbard and Heisenberg model the Herzberg circuit encircling the degeneracy point is realized by adiabatically tuning the successive on-site energies of quantum dots and tunnel couplings across a pair of neighboring dots. It is explicitly shown that encircling the degeneracy point leads to the accumulation of the geometrical Berry's phase. We show that only the triangular, not the linear, quantum dot molecule allows for the generation of Berry's phase and we discuss a protocol to detect this geometrical phase.

arXiv:1110.4983Physical Review BSep 6, 201223 citations

Controlling couplings between quantum dots in a quantum dot array

Lieven M. K. Vandersypen, Tzu-Kan Hsiao, Cornelis Jacobus van Diepen

Jan 1, 20210 citations

Anisotropic Spin Exchange in Coupled Quantum Dots

K. Foster, Layla Hormozi

APSMar 1, 20050 citations

Nonreciprocal Transmission and Reflection of a Chirally Coupled Quantum Dot

David L. Hurst, D. M. Price, C. Bentham +7 more

We report strongly nonreciprocal behavior for quantum dot exciton spins coupled to nanophotonic waveguides under resonant laser excitation. A clear dependence of the transmission spectrum on the propagation direction is found for a chirally coupled quantum dot, with spin up and spin down exciton spins coupling to the left and right propagation directions, respectively. The reflection signal shows an opposite trend to the transmission, which a numerical model indicates is due to direction-selective saturation of the quantum dot. The chiral spin-photon interface we demonstrate breaks reciprocity of the system and opens the way to spin-based quantum optical components such as optical diodes and circulators in a chip-based solid-state environment.We report strongly nonreciprocal behavior for quantum dot exciton spins coupled to nanophotonic waveguides under resonant laser excitation. A clear dependence of the transmission spectrum on the propagation direction is found for a chirally coupled quantum dot, with spin up and spin down exciton spins coupling to the left and right propagation directions, respectively. The reflection signal shows an opposite trend to the transmission, which a numerical model indicates is due to direction-selective saturation of the quantum dot. The chiral spin-photon interface we demonstrate breaks reciprocity of the system and opens the way to spin-based quantum optical components such as optical diodes and circulators in a chip-based solid-state environment.

arXiv:1801.09958Nano LettersAug 6, 201830 citations

S=1/2

. Using a Hubbard and Heisenberg model the Herzberg circuit encircling the degeneracy point is realized by adiabatically tuning the successive on-site energies of quantum dots and tunnel couplings across a pair of neighboring dots. It is explicitly shown that encircling the degeneracy point leads to the accumulation of the geometrical Berry's phase. We show that only the triangular, not the linear, quantum dot molecule allows for the generation of Berry's phase and we discuss a protocol to detect this geometrical phase.