The detection and characterization of paramagnetic species by electron spin resonance (ESR) spect... more The detection and characterization of paramagnetic species by electron spin resonance (ESR) spectroscopy is widely used throughout chemistry, biology and materials science, from in vivo imaging to distance measurements in spin-labelled proteins. ESR relies on the inductive detection of microwave signals emitted by the spins into a coupled microwave resonator during their Larmor precession. However, such signals can be very small, prohibiting the application of ESR at the nanoscale (for example, at the single-cell level or on individual nanoparticles). Here, using a Josephson parametric microwave amplifier combined with high-quality-factor superconducting microresonators cooled at millikelvin temperatures, we improve the state-of-the-art sensitivity of inductive ESR detection by nearly four orders of magnitude. We demonstrate the detection of 1,700 bismuth donor spins in silicon within a single Hahn echo with unit signal-to-noise ratio, reduced to 150 spins by averaging a single Carr...
Making and manipulating a weak-link qubit In superconductors, single particles cannot have energi... more Making and manipulating a weak-link qubit In superconductors, single particles cannot have energies smaller than the superconducting gap. Yet when two superconductors are separated by a thin nonsuperconducting bridge (the “weak link”), quasi-particles can occupy states that are inside the gap, the so-called Andreev bound states (ABSs). Janvier et al. fabricated such a structure out of superconducting aluminum and manipulated the occupation of a pair of ABSs. They observed oscillations in population between two of the energy levels, forming a type of qubit, which they dubbed the Andreev qubit. The results may lead to applications in quantum information processing. Science , this issue p. 1199
Proceedings of the National Academy of Sciences, 2015
An extensively pursued current direction of research in physics aims at the development of practi... more An extensively pursued current direction of research in physics aims at the development of practical technologies that exploit the effects of quantum mechanics. As part of this ongoing effort, devices for quantum information processing, secure communication, and high-precision sensing are being implemented with diverse systems, ranging from photons, atoms, and spins to mesoscopic superconducting and nanomechanical structures. Their physical properties make some of these systems better suited than others for specific tasks; thus, photons are well suited for transmitting quantum information, weakly interacting spins can serve as long-lived quantum memories, and superconducting elements can rapidly process information encoded in their quantum states. A central goal of the envisaged quantum technologies is to develop devices that can simultaneously perform several of these tasks, namely, reliably store, process, and transmit quantum information. Hybrid quantum systems composed of differ...
Laser Spectroscopy - Proceedings of the XV International Conference", 2002
Bohr, in his famous discussion with Einstein on complementarity, has stressed that the nature - q... more Bohr, in his famous discussion with Einstein on complementarity, has stressed that the nature - quantum or classical - of the interferometer parts plays an essential role to account for the fringes visibility. We have performed a Ramsey interferometry experiment with very excited Rydberg atoms, in which one "beam splitting" element is a classical field and the other - a
Laser Spectroscopy - Proceedings of the XVII International Conference, 2005
ABSTRACT Circular Rydberg states are sensitive probes of a millimeter-wave field stored in a supe... more ABSTRACT Circular Rydberg states are sensitive probes of a millimeter-wave field stored in a superconducting cavity. We show here that they can be used for a direct determination of two quasi-probability distributions in phase space, the Husimi-Q and the Wigner W functions, providing a detailed insight into the cavity mode quantum state. These experiments open the way to the study of non-local Schrödinger cat states, shared by two cavities.
The detection and characterization of paramagnetic species by electron spin resonance (ESR) spect... more The detection and characterization of paramagnetic species by electron spin resonance (ESR) spectroscopy is widely used throughout chemistry, biology and materials science, from in vivo imaging to distance measurements in spin-labelled proteins. ESR relies on the inductive detection of microwave signals emitted by the spins into a coupled microwave resonator during their Larmor precession. However, such signals can be very small, prohibiting the application of ESR at the nanoscale (for example, at the single-cell level or on individual nanoparticles). Here, using a Josephson parametric microwave amplifier combined with high-quality-factor superconducting microresonators cooled at millikelvin temperatures, we improve the state-of-the-art sensitivity of inductive ESR detection by nearly four orders of magnitude. We demonstrate the detection of 1,700 bismuth donor spins in silicon within a single Hahn echo with unit signal-to-noise ratio, reduced to 150 spins by averaging a single Carr...
Making and manipulating a weak-link qubit In superconductors, single particles cannot have energi... more Making and manipulating a weak-link qubit In superconductors, single particles cannot have energies smaller than the superconducting gap. Yet when two superconductors are separated by a thin nonsuperconducting bridge (the “weak link”), quasi-particles can occupy states that are inside the gap, the so-called Andreev bound states (ABSs). Janvier et al. fabricated such a structure out of superconducting aluminum and manipulated the occupation of a pair of ABSs. They observed oscillations in population between two of the energy levels, forming a type of qubit, which they dubbed the Andreev qubit. The results may lead to applications in quantum information processing. Science , this issue p. 1199
Proceedings of the National Academy of Sciences, 2015
An extensively pursued current direction of research in physics aims at the development of practi... more An extensively pursued current direction of research in physics aims at the development of practical technologies that exploit the effects of quantum mechanics. As part of this ongoing effort, devices for quantum information processing, secure communication, and high-precision sensing are being implemented with diverse systems, ranging from photons, atoms, and spins to mesoscopic superconducting and nanomechanical structures. Their physical properties make some of these systems better suited than others for specific tasks; thus, photons are well suited for transmitting quantum information, weakly interacting spins can serve as long-lived quantum memories, and superconducting elements can rapidly process information encoded in their quantum states. A central goal of the envisaged quantum technologies is to develop devices that can simultaneously perform several of these tasks, namely, reliably store, process, and transmit quantum information. Hybrid quantum systems composed of differ...
Laser Spectroscopy - Proceedings of the XV International Conference", 2002
Bohr, in his famous discussion with Einstein on complementarity, has stressed that the nature - q... more Bohr, in his famous discussion with Einstein on complementarity, has stressed that the nature - quantum or classical - of the interferometer parts plays an essential role to account for the fringes visibility. We have performed a Ramsey interferometry experiment with very excited Rydberg atoms, in which one "beam splitting" element is a classical field and the other - a
Laser Spectroscopy - Proceedings of the XVII International Conference, 2005
ABSTRACT Circular Rydberg states are sensitive probes of a millimeter-wave field stored in a supe... more ABSTRACT Circular Rydberg states are sensitive probes of a millimeter-wave field stored in a superconducting cavity. We show here that they can be used for a direct determination of two quasi-probability distributions in phase space, the Husimi-Q and the Wigner W functions, providing a detailed insight into the cavity mode quantum state. These experiments open the way to the study of non-local Schrödinger cat states, shared by two cavities.
Uploads
Papers