Related papers: Dissipative stabilization of squeezing beyond 3 dB…
We propose a protocol to measure impulses beyond the standard quantum limit. The protocol reduces noise in all three spatial dimensions and consists of squeezing a mechanical system's state via a series of jumps in the frequency of the…
A superconducting flux qubit is inductively coupled to a Superconducting QUantum Interference Device (SQUID) magnetometer, capacitively shunted to form a 1.294-GHz resonator. The qubit-state-dependent resonator frequency is weakly probed…
We measure frequency- and dissipation-quadrature noise in superconducting lithographed microwave resonators with sensitivity near the vacuum noise level using a Josephson parametric amplifier. At an excitation power of 100~nW, these…
Many superconducting qubit systems use the dispersive interaction between the qubit and a coupled harmonic resonator to perform quantum state measurement. Previous works have found that such measurements can induce state transitions in the…
Quantum noise limits the sensitivity of optical measurements, but squeezed states of light enable quantum-enhanced metrology, sensing, and information processing. Most on-chip squeezed-light sources rely on Kerr ($\chi^{(3)}$)…
Sensors based on whispering gallery resonators have minute footprints and can push achievable sensitivities and resolutions to their limits. Here, we use a microbubble resonator, with a wall thickness of 500 nm and an intrinsic Q-factor of…
Squeezed states of light are used for precision metrology and quantum-enhanced measurements, with applications spanning communication and sensing. State-of-the-art squeezed-light sources typically rely on optical cavities to achieve high,…
Quantum squeezing of mechanical resonator is important for studying the macroscopic quantum effects and the precision metrology of weak forces. Here we give a theoretical study of a hybrid atom-optomechanical system in which the…
We study rotating squeezed quantum states created by a parametric resonance in an open harmonic system. As a specific realization of the phenomenon we study a mesoscopic SQUID loop where the state preparation procedure is simple in…
Annual Review of Astronomy and Astrophysics, Volume 51, page 511e studied for coherently driven single photon sources, such as atoms and quantum dots. Maximal squeezing is realized, if the electronic subsystem of the emitter is in a pure…
We present a scheme by which projective homodyne measurement of a microwave resonator can be used to generate entanglement between two superconducting charge qubits coupled to this resonator. The non-interacting qubits are initialised in a…
In the context of engineered quantum systems, there is a demand for superconducting tunable devices able to operate with high Q-factors at power levels equivalent to only a few photons. In this work, we developed a 3D microwave reentrant…
Strongly squeezed light at telecommunication wavelengths is the necessary resource for one-sided device-independent quantum key distribution via fibre networks. Reducing the optical pump power that is required for its generation will…
Wigner function tomography is indispensable for characterizing quantum states, but its commonly used version, balanced homodyne detection, suffers from several weaknesses. First, it requires efficient detection, which is critical for…
At absolute zero temperature, thermal noise vanishes when a physical system is in its ground state, but quantum noise remains as a fundamental limit to the accuracy of experimental measurements. Such a limitation, however, can be mitigated…
We autonomously stabilize arbitrary states of a qubit through parametric modulation of the coupling between a fixed frequency qubit and resonator. The coupling modulation is achieved with a tunable coupler design, in which the qubit and the…
Quantum metrology utilizes nonclassical states to improve the precision of measurement devices. In this context, strongly squeezed vacuum states of light have proven to be a useful resource. They are typically produced by spontaneous…
Squeezed states of light have received renewed attention due to their applicability to quantum-enhanced sensing. To take full advantage of their reduced noise properties to enhance atomic-based sensors, it is necessary to generate…
We experimentally demonstrate the steady-state generation of propagating Wigner-negative states from a continuously driven superconducting qubit. We reconstruct the Wigner function of the radiation emitted into propagating modes defined by…
We achieved continuous-wave 8.3-dB squeezed light generation using a terahertz-order-broadband waveguide optical parametric amplifier (OPA) by improving a measurement setup from our previous work [T. Kashiwazaki, et al., Appl. Phys. Lett.…