Approaching Maximal Precision of Hong-Ou-Mandel Interferometry with Nonperfect Visibility.

In quantum mechanics, the precision achieved in parameter estimation using a quantum state as a probe is determined by the measurement strategy employed. The quantum limit of precision is bounded by a value set by the state and its dynamics. Theoretical results have revealed that in interference measurements with two possible outcomes, this limit can be reached under ideal conditions of perfect visibility and zero losses.

Gottesman-Kitaev-Preskill Encoding in Continuous Modal Variables of Single Photons.

GKP states, introduced by Gottesman, Kitaev, and Preskill, are continuous variable logical qubits that can be corrected for errors caused by phase space displacements. Their experimental realization is challenging, in particular, using propagating fields, where quantum information is encoded in the quadratures of the electromagnetic field. However, traveling photons are essential in many applications of GKP codes involving the long-distance transmission of quantum information.

Quantum Metrology Using Time-Frequency as Quantum Continuous Variables: Resources, Sub-Shot-Noise Precision and Phase Space Representation.

We study the role of the electromagnetic field's frequency on the precision limits of time measurements from a quantum perspective, using single photons as a paradigmatic system. We demonstrate that a quantum enhancement of precision is possible only when combining both intensity and spectral resources and, in particular, that spectral correlations enable a quadratic scaling of precision with the number of probes. We identify the general mathematical structure of nonphysical states that achieve the Heisenberg limit and show how a finite spectral variance may cause a quantum-to-classical-like transition in precision scaling for pure states similar to the one observed for noisy systems.

Dietary Therapies Induce Rapid Response and Remission in Pediatric Patients With Active Crohn's Disease.

Background & Aims: Dietary therapies based on exclusion of usual dietary elements induce remission in children with Crohn's disease (CD), whereas re-exposure induces rebound inflammation. We investigated whether a short trial of dietary therapy, to identify patients with and without a rapid response or remission on the diet (DiRe), can be used to predict success or failure of long-term dietary therapy.

Methods: We collected data from the multicenter randomized trial of the CD exclusion diet (CDED).

Demonstration of an Effective Ultrastrong Coupling between Two Oscillators.

When the coupling rate between two quantum systems becomes as large as their characteristic frequencies, it induces dramatic effects on their dynamics and even on the nature of their ground state. The case of a qubit coupled to a harmonic oscillator in this ultrastrong coupling regime has been investigated theoretically and experimentally. Here, we explore the case of two harmonic oscillators in the ultrastrong coupling regime.