Publications de Liu Qiu | EPFL Graph Search

Dissipative Quantum Feedback in Measurements Using a Parametrically Coupled Microcavity

Tobias Kippenberg, Liu Qiu, Itay Shomroni, Guanhao Huang

Micro- and nanoscale optical or microwave cavities are used in a wide range of classical applications and quantum science experiments, ranging from precision measurements, laser technologies to quantum control of mechanical motion. The dissipative photon l ...

AMER PHYSICAL SOC2022

A cryogenic electro-optic interconnect for superconducting devices

Tobias Kippenberg, Nathan Rafaël Bernier, Liu Qiu, Itay Shomroni, Amir Youssefi, Anton Lukashchuk

A major challenge to the scalability of cryogenic computing platforms is the heat load associated with the growing number of electrical cable connections between the superconducting circuitry and the room-temperature environment. Compared with electrical c ...

2021

Optomechanical generation of a mechanical catlike state by phonon subtraction

Tobias Kippenberg, Liu Qiu, Itay Shomroni

We propose a scheme to prepare a macroscopic mechanical oscillator in a catlike state, close to a coherent state superposition. The mechanical oscillator, coupled by radiation-pressure interaction to a field in an optical cavity, is first prepared close to ...

AMER PHYSICAL SOC2020

Laser Cooling of a Nanomechanical Oscillator to Its Zero-Point Energy

Tobias Kippenberg, Liu Qiu, Itay Shomroni

Optomechanical systems in the well-resolved-sideband regime are ideal for studying a myriad of quantum phenomena with mechanical systems, including backaction-evading measurements, mechanical squeezing, and nonclassical states generation. For these experim ...

AMER PHYSICAL SOC2020

Quantum Measurement of Mechanical Motion close to the Standard Quantum Limit

Liu Qiu

In quantum mechanics, the Heisenberg uncertainty principle places a fundamental limit in the measurement precision for certain pairs of physical quantities, such as position and momentum, time and energy or amplitude and phase. Due to the Heisenberg uncert ...

EPFL2020

Two-Tone Optomechanical Instability and Its Fundamental Implications for Backaction-Evading Measurements

Tobias Kippenberg, Liu Qiu, Itay Shomroni, Amir Youssefi

While quantum mechanics imposes a fundamental limit on the precision of interferometric measurementsof mechanical motion due to measurement backaction, the nonlinear nature of the coupling also leads toparametric instabilities that place practical limits o ...

American Physical Society2019

Floquet dynamics in the quantum measurement of mechanical motion

Tobias Kippenberg, Nicolas Piro Mastracchio, Marie Adrienne Ioannou, Liu Qiu, Itay Shomroni

The radiation-pressure interaction between one or more laser fields and a mechanical oscillator gives rise to a wide range of phenomena: From sideband cooling and backaction-evading measurements to ponderomotive and mechanical squeezing to entanglement and ...

2019

Optical backaction-evading measurement of a mechanical oscillator

Tobias Kippenberg, Liu Qiu, Itay Shomroni

Quantum mechanics imposes a limit on the precision of a continuous position measurement of a harmonic oscillator, due to backaction arising from quantum fluctuations in the measurement field. This standard quantum limit can be surpassed by monitoring only ...

Springer2019

Quantum Motional Sideband Asymmetry in the Presence of Kerr-type Nonlinearities

Tobias Kippenberg, Marie Adrienne Ioannou, Liu Qiu, Itay Shomroni

Sideband asymmetry between the Stokes and anti-Stokes scattering is a signature of the mechanical oscillators in the quantum regime. It has been demonstrated in several optomechanical systems, as a self-calibrated thermometry method. We present motional si ...

IEEE2018

Backaction-evading measurement of mechanical motion in the optical domain

Tobias Kippenberg, Liu Qiu, Itay Shomroni

When measuring the position of a mechanical oscillator, quantum mechanics imposes a strict limit on the attainable precision: Any reduction of imprecision leads to increased quantum backaction of the measuring probe on the oscillator. This quantum limit ca ...

IEEE2018