Motion analysis in patients with postpartum sacroiliac joint dysfunction: A cross-sectional case-control study.

Background: Patients with sacroiliac joint dysfunction are limited in daily life activities such as gait, climbing stairs and rising from a chair. It is well known that individuals with chronic low back pain have impaired balance compared to healthy individuals. This cross-sectional case-control study aims to investigate spatiotemporal parameters, center of pressure and mass, pelvic angles and other joint angles in patients with sacroiliac joint dysfunction in comparison with healthy controls.

Assembly and coherent control of a register of nuclear spin qubits.

The generation of a register of highly coherent, but independent, qubits is a prerequisite to performing universal quantum computation. Here we introduce a qubit encoded in two nuclear spin states of a single Sr atom and demonstrate coherence approaching the minute-scale within an assembled register of individually-controlled qubits. While other systems have shown impressive coherence times through some combination of shielding, careful trapping, global operations, and dynamical decoupling, we achieve comparable coherence times while individually driving multiple qubits in parallel.

40 W, 780 nm laser system with compensated dual beam splitters for atom interferometry.

We demonstrate a narrow-linewidth 780 nm laser system with up to 40 power and a frequency modulation bandwidth of 230 MHz. Efficient overlap on nonlinear optical elements combines two pairs of phase-locked frequency components into a single beam. Serrodyne modulation with a high-quality sawtooth waveform is used to perform frequency shifts with >96.

Effective Inertial Frame in an Atom Interferometric Test of the Equivalence Principle.

In an ideal test of the equivalence principle, the test masses fall in a common inertial frame. A real experiment is affected by gravity gradients, which introduce systematic errors by coupling to initial kinematic differences between the test masses. Here we demonstrate a method that reduces the sensitivity of a dual-species atom interferometer to initial kinematics by using a frequency shift of the mirror pulse to create an effective inertial frame for both atomic species.

Erratum: Comparison of Spectral Linewidths for Quantum Degenerate Bosons and Fermions [Phys. Rev. Lett. 117, 213001 (2016)].

This corrects the article DOI: 10.1103/PhysRevLett.117.