Quantum-mechanical effects at the macroscopic level were first explored in Josephson-
junction-based superconducting circuits in the 1980s. In recent decades, the emergence of …

Full manipulation of a quantum system requires controlled evolution generated by nonlinear
interactions, which is coherent when the rate of nonlinearity is large compared with the rate …

Many important phenomena in quantum devices are dynamic, meaning that they cannot be
studied using time-averaged measurements alone. Experiments that measure such transient …

Detection of the weakest forces in nature is aided by increasingly sensitive measurements of
the motion of mechanical oscillators. However, the attainable knowledge of an oscillator's …

Quantum computing offers a powerful new paradigm of information processing that has the
potential to transform a wide range of industries. In the pursuit of the tantalizing promises of …

Squeezing of the electromagnetic vacuum is an essential metrological technique used to
reduce quantum noise in applications spanning gravitational wave detection, biological …

We have realized a new interaction between superconducting qubits and a readout cavity
that results in the displacement of a coherent state in the cavity, conditioned on the state of …

While the squeezing of a propagating field can, in principle, be made arbitrarily strong, the
cavity-field squeezing is subject to the well-known 3 dB limit, and thus has limited …

It has been a long-standing goal to improve dispersive qubit readout with squeezed light.
However, injected external squeezing (IES) cannot enable a practically interesting increase …

Vacuum fluctuations of the electromagnetic field set a fundamental limit to the sensitivity of a
variety of measurements, including magnetic resonance spectroscopy. We report the use of …