Quantum Science

In the emerging field of quantum thermodynamics, heat transport and dissipation in a quantum electronic device is a fundamentally important topic. Gate-tunable single-quantum dot junctions are paradigmatic test benches for quantum transport. Whereas the study of charge transport therein has already allowed exploring a large palette of physical effects at... Read more
Published on: 2020-01-23
Photon pairs produced in spontaneous parametric down-conversion are naturally entangled in their transverse spatial degrees of freedom including the orbital angular momentum. Pumping a non-linear crystal with a zero order Gaussian mode produces quantum correlated signal and idler photons with equal orbital angular momentum and opposite signs. Measurements performed on... Read more
Published on: 2020-01-23
The article introduces efficient quantum state tomography schemes for qutrits and entangled qubits subject to pure decoherence. We implement the dynamic state reconstruction method for open systems sent through phase-damping channels which was proposed in: Open Syst. Inf. Dyn. 23, 1650019 (2016). In the current article we prove that two... Read more
Published on: 2020-01-23
For a moving atom, the spontaneous emission rate is modified due to the contributions from two factors, the R"{o}ntgen interaction term and the recoil effect induced by the emitted photon. Here we investigate the emission rate of a uniformly moving atom near a perfectly conducting plate and obtain the corrections... Read more
Published on: 2020-01-23
Femtosecond laser writing is a powerful technique that allows rapid and cost-effective fabrication of photonic integrated circuits with unique 3D geometries, which today are playing upfront in quantum photonics applications. The possibility to reconfigure such devices by thermo-optic phase shifters represents a paramount feature, exploited to produce adaptive and programmable... Read more
Published on: 2020-01-23
One of the central principles of quantum mechanics is that if there are multiple paths that lead to the same event, and there is no way to distinguish between them, interference occurs. It is usually assumed that distinguishing information in the preparation, evolution or measurement of a system is sufficient... Read more
Published on: 2020-01-23
For quantum systems with a total dimension greater than six, the positive partial transposition (PPT) criterion is sufficient but not necessary to decide the non-separability of quantum states. Here, we present an Automated Machine Learning approach to classify random states of two qutrits as separable or entangled using enough data... Read more
Published on: 2020-01-23
Measurement-device-independent quantum key distribution (MDI-QKD) can remove all detection side-channels from quantum communication systems. The security proofs require, however, that certain assumptions on the sources are satisfied. This includes, for instance, the requirement that there is no information leakage from the transmitters of the senders, which unfortunately is very difficult... Read more
Published on: 2020-01-23
Contracting tensor networks is often computationally demanding. Well-designed contraction sequences can dramatically reduce the contraction cost. We explore the performance of simulated annealing and genetic algorithms, two common discrete optimization techniques, to this ordering problem. We benchmark their performance as well as that of the commonly-used greedy search on physically... Read more
Published on: 2020-01-23
The calculation of work distributions in a quantum many-body system is of significant importance and also of formidable difficulty in the field of nonequilibrium quantum statistical mechanics. To solve this problem, inspired by Schwinger-Keldysh formalism, we propose the contour-integral formulation of the work statistics. Based on this contour integral, we... Read more
Published on: 2020-01-23