Quantum control of a cat qubit with bit-flip times exceeding ten seconds.

Quantum bits (qubits) are prone to several types of error as the result of uncontrolled interactions with their environment. Common strategies to correct these errors are based on architectures of qubits involving daunting hardware overheads. One possible solution is to build qubits that are inherently protected against certain types of error, so the overhead required to correct the remaining errors is greatly reduced.

Using Spontaneous Emission of a Qubit as a Resource for Feedback Control.

Persistent control of a transmon qubit is performed by a feedback protocol based on continuous heterodyne measurement of its fluorescence. By driving the qubit and cavity with microwave signals whose amplitudes depend linearly on the instantaneous values of the quadratures of the measured fluorescence field, we show that it is possible to stabilize permanently the qubit in any targeted state. Using a Josephson mixer as a phase-preserving amplifier, it was possible to reach a total measurement efficiency η=35%, leading to a maximum of 59% of excitation and 44% of coherence for the stabilized states.

Stabilization of nonclassical states of the radiation field in a cavity by reservoir engineering.

We propose an engineered reservoir inducing the relaxation of a cavity field towards nonclassical states. It is made up of two-level atoms crossing the cavity one at a time. Each atom-cavity interaction is first dispersive, then resonant, then dispersive again.

Differential histone deacetylase mRNA expression patterns in amyotrophic lateral sclerosis.

Histone deacetylases (HDACs) are important regulators of gene expression and cell differentiation. The HDAC inhibitors have recently been considered as potential novel neuroprotective drugs for the treatment of neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS). A major limitation, however, lies in the broad spectrum of action of currently available HDAC inhibitors that may cause a variety of toxic side effects.