We realize on an Atom-Chip a practical, experimentally undemanding, tomographic reconstruction al... more We realize on an Atom-Chip a practical, experimentally undemanding, tomographic reconstruction algorithm relying on the time-resolved measurements of the atomic population distribution among atomic internal states. More specifically, we estimate both the state density matrix as well as the dephasing noise present in our system by assuming complete knowledge of the Hamiltonian evolution. The proposed scheme is based on routinely performed measurements and established experimental procedures, hence providing a simplified methodology for quantum technological applications.
Atomic memories for flying photonic qubits are an essential ingredient for many applications like... more Atomic memories for flying photonic qubits are an essential ingredient for many applications like e.g. quantum repeaters. Verification of the coherent transfer of information from a light field to an atomic superposition is usually obtained using an optical read-out. In this paper we report the direct detection of the atomic coherence by means of atom interferometry. We experimentally verified both that a bichromatic laser field closing a Raman transition imprints a distinct, controllable phase on the atomic coherence and that it can be recovered after a variable time delay.
ABSTRACT The interaction of the radiation pressure with micro-mechanical oscillators is earning a... more ABSTRACT The interaction of the radiation pressure with micro-mechanical oscillators is earning a growing interest for its wide-range applications and for fundamental research. In this contribution we describe the fabrication of a family of opto-mechanical devices specifically designed to ease the detection of ponderomotive squeezing and of entanglement between macroscopic objects and light. These phenomena are not easily observed, due to the overwhelming effects of classical noise sources of thermal origin with respect to the weak quantum fluctuations of the radiation pressure. A low thermal noise background is required, together with a weak interaction between the micro-mirror and this background (i.e. high mechanical quality factors). In the development of our opto-mechanical devices, we heve explored an approach focused on relatively thick silicon oscillators with high reflectivity coating. The relatively high mass is compensated by the capability to manage high power at low temperatures, owing to a favourable geometric factor (thicker connectors) and the excellent thermal conductivity of silicon crystals at cryogenic temperature. We have measured at cryogenic temperatures mechanical quality factors up to 105 in a micro-oscillator designed to reduce as much as possible the strain in the coating layer and the consequent energy dissipation. This design improves an approach applied in micro-mirror and micro-cantilevers, where the coated surface is reduced as much as possible to improve the quality factor. The deposition of the highly reflective coating layer has been carefully integrated in the micro-machining process to preserve its low optical losses.
The non-equilibrium dynamics of the superradiant scattering of light from a BEC is experimentally... more The non-equilibrium dynamics of the superradiant scattering of light from a BEC is experimentally investigated by monitoring the time evolution of the population in the condensate. In the experiment, a cigar-shaped Bose-Einstein condensate of 87Rb atoms is produced and is exposed to a single off-resonant laser pulse directed along the condensate symmetry axis. The superradiant back-scattering of light creates a
ABSTRACT The present work investigates quantum phenomena with large size systems generated in the... more ABSTRACT The present work investigates quantum phenomena with large size systems generated in the microscopic world and then transferred in the macro one through an amplification process. Precisely, a microscopic entangled photon state is created by a nonlinear optical process, then one subsystem is injected into an optical parametric amplifier and then converted into a macro — state consisting of N ≈ 3.5 × 104 photons in a quantum superposition. By adopting a local filtering technique, we then demonstrate the entanglement of the bipartite system. The new conceptual framework paves the way toward the generation of light-matter entangled states by coupling the output radiation with a Bose-Einstein condensate. The multiphoton superposition generated by a quantum-injected optical parametric amplifier (QI-OPA) can be made to interact with a Mirror-BEC shaped as a Bragg interference structure.
The contribution of Theodore Hansch to scientific progress in the field of the interaction betwee... more The contribution of Theodore Hansch to scientific progress in the field of the interaction between light and matter has been impressive, continuous and ubiquitous during the last 35 years. The oldest of us still remember the world impact of the first saturation and two-...
We present the quantum theory of a polarization phase gate that can be realized in a sample of ul... more We present the quantum theory of a polarization phase gate that can be realized in a sample of ultracold rubidium atoms driven into a tripod configuration. The main advantages of this scheme are its relative simplicity and inherent symmetry. It is shown that conditional phase shifts of order π can be attained.
We realize on an Atom-Chip a practical, experimentally undemanding, tomographic reconstruction al... more We realize on an Atom-Chip a practical, experimentally undemanding, tomographic reconstruction algorithm relying on the time-resolved measurements of the atomic population distribution among atomic internal states. More specifically, we estimate both the state density matrix as well as the dephasing noise present in our system by assuming complete knowledge of the Hamiltonian evolution. The proposed scheme is based on routinely performed measurements and established experimental procedures, hence providing a simplified methodology for quantum technological applications.
Atomic memories for flying photonic qubits are an essential ingredient for many applications like... more Atomic memories for flying photonic qubits are an essential ingredient for many applications like e.g. quantum repeaters. Verification of the coherent transfer of information from a light field to an atomic superposition is usually obtained using an optical read-out. In this paper we report the direct detection of the atomic coherence by means of atom interferometry. We experimentally verified both that a bichromatic laser field closing a Raman transition imprints a distinct, controllable phase on the atomic coherence and that it can be recovered after a variable time delay.
ABSTRACT The interaction of the radiation pressure with micro-mechanical oscillators is earning a... more ABSTRACT The interaction of the radiation pressure with micro-mechanical oscillators is earning a growing interest for its wide-range applications and for fundamental research. In this contribution we describe the fabrication of a family of opto-mechanical devices specifically designed to ease the detection of ponderomotive squeezing and of entanglement between macroscopic objects and light. These phenomena are not easily observed, due to the overwhelming effects of classical noise sources of thermal origin with respect to the weak quantum fluctuations of the radiation pressure. A low thermal noise background is required, together with a weak interaction between the micro-mirror and this background (i.e. high mechanical quality factors). In the development of our opto-mechanical devices, we heve explored an approach focused on relatively thick silicon oscillators with high reflectivity coating. The relatively high mass is compensated by the capability to manage high power at low temperatures, owing to a favourable geometric factor (thicker connectors) and the excellent thermal conductivity of silicon crystals at cryogenic temperature. We have measured at cryogenic temperatures mechanical quality factors up to 105 in a micro-oscillator designed to reduce as much as possible the strain in the coating layer and the consequent energy dissipation. This design improves an approach applied in micro-mirror and micro-cantilevers, where the coated surface is reduced as much as possible to improve the quality factor. The deposition of the highly reflective coating layer has been carefully integrated in the micro-machining process to preserve its low optical losses.
The non-equilibrium dynamics of the superradiant scattering of light from a BEC is experimentally... more The non-equilibrium dynamics of the superradiant scattering of light from a BEC is experimentally investigated by monitoring the time evolution of the population in the condensate. In the experiment, a cigar-shaped Bose-Einstein condensate of 87Rb atoms is produced and is exposed to a single off-resonant laser pulse directed along the condensate symmetry axis. The superradiant back-scattering of light creates a
ABSTRACT The present work investigates quantum phenomena with large size systems generated in the... more ABSTRACT The present work investigates quantum phenomena with large size systems generated in the microscopic world and then transferred in the macro one through an amplification process. Precisely, a microscopic entangled photon state is created by a nonlinear optical process, then one subsystem is injected into an optical parametric amplifier and then converted into a macro — state consisting of N ≈ 3.5 × 104 photons in a quantum superposition. By adopting a local filtering technique, we then demonstrate the entanglement of the bipartite system. The new conceptual framework paves the way toward the generation of light-matter entangled states by coupling the output radiation with a Bose-Einstein condensate. The multiphoton superposition generated by a quantum-injected optical parametric amplifier (QI-OPA) can be made to interact with a Mirror-BEC shaped as a Bragg interference structure.
The contribution of Theodore Hansch to scientific progress in the field of the interaction betwee... more The contribution of Theodore Hansch to scientific progress in the field of the interaction between light and matter has been impressive, continuous and ubiquitous during the last 35 years. The oldest of us still remember the world impact of the first saturation and two-...
We present the quantum theory of a polarization phase gate that can be realized in a sample of ul... more We present the quantum theory of a polarization phase gate that can be realized in a sample of ultracold rubidium atoms driven into a tripod configuration. The main advantages of this scheme are its relative simplicity and inherent symmetry. It is shown that conditional phase shifts of order π can be attained.
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Papers by F. Cataliotti