Quantum 7, 891 (2023). https://doi.org/10.22331/q-2023-01-03-891 Consistent dynamics which couples classical and quantum degrees of freedom exists, provided it is stochastic. This dynamics is linear in the hybrid state, completely positive and trace preserving. One application […]
Quantum 7, 890 (2023). https://doi.org/10.22331/q-2023-01-03-890 We show that $Omega(rd/epsilon)$ copies of an unknown rank-$r$, dimension-$d$ quantum mixed state are necessary in order to learn a classical description with $1 – epsilon$ fidelity. This improves upon […]
Quantum 7, 889 (2023). https://doi.org/10.22331/q-2023-01-03-889 Measuring the expectation value of the molecular electronic Hamiltonian is one of the challenging parts of the variational quantum eigensolver. A widely used strategy is to express the Hamiltonian as […]
Quantum 7, 888 (2023). https://doi.org/10.22331/q-2023-01-03-888 Recent advances in laser interactions with coherent free electrons have enabled to shape the electron’s quantum state. Each electron becomes a superposition of energy levels on an infinite quantized ladder, […]
Quantum 6, 887 (2022). https://doi.org/10.22331/q-2022-12-29-887 Spin squeezing inequalities (SSI) represent a major tool to probe quantum entanglement among a collection of few-level atoms, and are based on collective spin measurements and their fluctuations. Yet, for […]
Quantum 6, 886 (2022). https://doi.org/10.22331/q-2022-12-29-886 We study the emergence over time of a universal, uniform distribution of quantum states supported on a finite subsystem, induced by projectively measuring the rest of the system. Dubbed $textit{deep […]
Quantum 6, 885 (2022). https://doi.org/10.22331/q-2022-12-29-885 We study the quantum synchronization of a single spin driven by an external semiclassical signal for spin numbers larger than $S = 1$, the smallest system to host a quantum […]
Quantum 6, 884 (2022). https://doi.org/10.22331/q-2022-12-22-884 Quantum speed limits (QSLs) identify fundamental time scales of physical processes by providing lower bounds on the rate of change of a quantum state or the expectation value of an […]
Quantum 6, 883 (2022). https://doi.org/10.22331/q-2022-12-22-883 Equivalent approaches to determine eigenfrequencies of the Liouvillians of open quantum systems are discussed using the solution of the Heisenberg-Langevin equations and the corresponding equations for operator moments. A simple […]
Quantum 6, 882 (2022). https://doi.org/10.22331/q-2022-12-22-882 This paper is concerned with complexity theoretic aspects of a general formulation of quantum game theory that models strategic interactions among rational agents that process and exchange quantum information. In […]
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