PERSPECTIVE
The authors offer an overview of progress and a future perspective of large-scale optical quantum entanglement. They cover a broad range of topics from the basics of continuous-variable optical quantum entanglement and a multiplexing methodology for the generation of large-scale quantum entanglement to future approaches toward practical usages of large-scale optical quantum entanglement. The content includes both pedagogical content and the search for future directions beyond the current frontier.
Warit Asavanant and Akira Furusawa
Phys. Rev. A 109, 040101 (2024)
EDITORS' SUGGESTION
The authors theoretically analyze the performance of long-distance quantum communication protocols, specifically quantum repeaters based on Gottesman-Kitaev-Preskill (GKP) qudits. Previously, only the qubit case has been studied. They construct three quantum repeater schemes and find that, while in most cases any benefits of using higher dimensions is negated by worse error correction, there are some regimes where the use of qubits does increase the secret key rate.
Frank Schmidt, Daniel Miller, and Peter van Loock
Phys. Rev. A 109, 042427 (2024)
LETTER
The authors investigate the nonequilibrium dynamics of the order parameter of a fermionic condensate following an abrupt change in the pairing interaction at nonzero temperature. They express the magnitude of the resulting oscillations with Tan’s contact, and identify strong thermal effects as the temperature approaches the critical value, in particular for the nonlinear evolution which follows deep quenches.
H. Kurkjian et al.
Phys. Rev. A 109, L041302 (2024)
LETTER
This work focuses on enhancing the dispersive readout of a single electron spin qubit by utilizing displaced squeezed vacuum states for the probe photons. The built-in quantum correlations of squeezed photons lead to significant improvements in qubit readout fidelity and speed.
Chon-Fai Kam and Xuedong Hu
Phys. Rev. A 109, L040402 (2024)
LETTER
The authors establish a connection between nonstabilizerness and a readily measurable property – the entanglement spectrum. This connection not only provides a deeper understanding of quantum complexity but also offers a practical way to probe nonstabilizerness even in noisy environments.
Emanuele Tirrito et al.
Phys. Rev. A 109, L040401 (2024)
LETTER
Many-body theory is used to study positron binding in halogenated hydrocarbons . As well as reproducing recent experimental binding energies, the general effect of halogenation is discussed and explained: fluorinated molecules generate a weaker positron-molecule correlation potential than their chlorinated and brominated counterparts owing to fluorinated molecules having higher molecular orbital ionization energies and a lower density of electron states near the highest occupied molecular orbitals.
J. P. Cassidy et al.
Phys. Rev. A 109, L040801 (2024)
LETTER
In a parity-time (PT) symmetric photonic dimer structure, the authors analytically obtained the phase diagram with quantum jumps induced by loss and gain, defined a Hermitian exchange operator to characterize different PT phases, and engineered the quantum state and Hong-Ou-Mandel interferences. Their study paves the way for quantum state engineering, quantum interferences, and logic operations in non-Hermitian photonic systems.
Xinchen Zhang et al.
Phys. Rev. A 109, L041503 (2024)
LETTER
The authors show that a resonator designed to operate at an absorbing exceptional point is substantially better at capturing a naturally emitted decaying waveform than a conventional cavity with a similar factor. This enhanced performance can lead to improved protocols for classical and quantum state transfer between resonant cavities.
Asaf Farhi et al.
Phys. Rev. A 109, L041502 (2024)
EDITORS' SUGGESTION
The authors study the interaction between two polar molecules in rotational states differing by two or more quanta. They find that the resultant repulsive van der Waals interaction can potentially suppress collisional losses at low temperatures.
Etienne F. Walraven and Tijs Karman
Phys. Rev. A 109, 043310 (2024)
LETTER
The authors derive bounds on the suppression of the bandwidth-integrated local density of states (LDOS). They show that effective one-dimensional gratings which support a slow light mode can achieve near-perfect LDOS suppression even in the presence of material loss.
Benjamin Strekha et al.
Phys. Rev. A 109, L041501 (2024)
LETTER
The work challenges the concept of “classical independence” between physical systems by demonstrating that within quantum theory two systems can affect each other despite no observable changes, unveiling the interconnected nature of the quantum world. The findings also unveil potential applications for device-independent certification of quantum states and measurements.
Shubhayan Sarkar
Phys. Rev. A 109, L040202 (2024)
LETTER
The authors measure transverse spin correlations in energy space to uncover hidden spin dynamics in a weakly interacting Fermi gas. The correlation functions reveal the microscopic structure of a demagnetizing or magnetizing synthetic spin lattice, which models a collective Heisenberg Hamiltonian, and provide new observables for studies of transitions between dynamical phases.
J. Huang and J. E. Thomas
Phys. Rev. A 109, L041301 (2024)
LETTER
The authors find a harmonic enhancement structure in the high-order harmonic generation spectrum of graphene. Further investigation indicates that the structure is associated with the bunching of multiple interband electron-hole recombination trajectories, in analogy to the focusing behavior of light rays known as caustics.
Fulong Dong, Qinzhi Xia, and Jie Liu
Phys. Rev. A 109, L041102 (2024)
