Enrico Tesio - Academia.edu (original) (raw)
Papers by Enrico Tesio
arXiv (Cornell University), Aug 6, 2013
2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)
The spontaneous emergence of spatiotemporal order is a prominent feature of physical systems driv... more The spontaneous emergence of spatiotemporal order is a prominent feature of physical systems driven far from equilibrium. Recent experimental works have provided paradigmatic examples in transverse nonlinear optics with cold atoms such as spatial (optomechanical) or magnetic ordering [1], [2]. In the first case, the bunching of atoms due to dipole forces provides positive feedback leading to multimode symmetry breaking.
2013 Sixth "Rio De La Plata" Workshop on Laser Dynamics and Nonlinear Photonics, 2013
We discuss the formation of optomechanical structures from the interaction between linear dielect... more We discuss the formation of optomechanical structures from the interaction between linear dielectric scatterers and a light field via dipole forces without the need for optical nonlinearities. The experiment uses a high density sample of Rb atoms in a single mirror feedback geometry. We observe hexagonal structures in the light field and a complementary honeycomb pattern in the atomic density. Different theoretical approaches are discussed assuming either viscous damping of the atomic velocity or not. The interplay between electronic and optomechanical nonlinearities is analyzed. A prediction for dissipative light-matter density solitons is given. The investigations demonstrate novel prospects for the manipulation of matter in a pattern forming system in which quantum effects should be accessible.
Advanced Photonics, 2014
Experimental, theoretical and numerical evidence of optomechanical self-structuring of a laser be... more Experimental, theoretical and numerical evidence of optomechanical self-structuring of a laser beam in a cloud of cold atoms in a single-mirror feedback configuration is presented. Optomechanical dissipative solitons can be encoded in the atomic density.
Nonlinear Optics, 2013
We demonstrate an optomechanical instability in a sample of cold atoms driven by a single laser b... more We demonstrate an optomechanical instability in a sample of cold atoms driven by a single laser beam in presence of a feedback mirror. Hexagonal light filaments propagate in atom-depleted tubes forming a honeycomb lattice.
Optics Express, 2013
We investigate the coupled dynamics of light and cold atoms in a unidirectional ring cavity, in t... more We investigate the coupled dynamics of light and cold atoms in a unidirectional ring cavity, in the regime of low saturation and linear single-atom response. As the dispersive opto-mechanical coupling between light and the motional degrees of freedom of the atoms makes the dynamics nonlinear, we find that localized, nonlinearity-sustained and bistable structures can be encoded in the atomic density by means of appropriate control beams.
Physical Review A, 2012
Transverse pattern formation in an optical cavity containing a cloud of cold two-level atoms is d... more Transverse pattern formation in an optical cavity containing a cloud of cold two-level atoms is discussed. We show that density modulation becomes the dominant mechanism as the atomic temperature is reduced. Indeed, for low but achievable temperatures the internal degrees of freedom of the atoms can be neglected, and the system is well described by treating them as mobile dielectric particles. A linear stability analysis predicts the instability threshold and the spatial scale of the emergent pattern. Numerical simulations in one and two transverse dimensions confirm the instability and predict honeycomb and hexagonal density structures, respectively, for the blue and red detuned cases.
This text may be downloaded only for personal research purposes. Any additional reproduction for ... more This text may be downloaded only for personal research purposes. Any additional reproduction for other purposes, whether in hard copies or electronically, requires the consent of the Florence School of Regulation.
We theoretically investigate the specific heat in the normal state of an ultracold Fermi gas. Usi... more We theoretically investigate the specific heat in the normal state of an ultracold Fermi gas. Using a strong-coupling BCS-BEC crossover theory, we clarify how strong pairing fluctuations affect this quantity in the whole BCS-BEC crossover region. Recently, the specific heat has been measured in the unitarity limit of this system[1], exhibiting a lambda-like temperature dependence near the superfluid phase transition temperature, as opposed to the well-known Tlinear behavior obtained in normal Fermi liquids. We examine whether this anomalous temperature dependence is due to strong pairing fluctuations. We also discuss effects of the socalled pseudogap phenomenon on the specific heat. Since the existence of strong pairing fluctuations is a crucial key in understanding the BCS-BEC crossover physics, our results would be helpful in elucidating their effects on the thermodynamic properties of an ultracold Fermi gas.
Physical Review Letters, 2015
Physical Review B, 2015
We consider a system composed by N atoms trapped within a multimode cavity, whose theoretical des... more We consider a system composed by N atoms trapped within a multimode cavity, whose theoretical description is captured by a disordered multimode Dicke model. We show that in the resonant, zero-field limit the system exactly realizes the Sherrington-Kirkpatrick model. Upon a redefinition of the temperature, the same dynamics is realized in the dispersive, strong-field limit. This regime also gives access to spin-glass observables which can be used to detect replica symmetry breaking.
form only given. Spontaneous optical pattern formation occurs in a variety of nonlinear systems [... more form only given. Spontaneous optical pattern formation occurs in a variety of nonlinear systems [1], including hot atomic vapors [2]. On the other hand, the spatial self-organization of atomic ensembles due to opto-mechanical coupling has received a lot of interest in recent years [3].We report on the observation of transverse self-organization of a cold atomic cloud (issued from a magnetooptical trap) under the action of a single pump laser beam. Two symmetries (translation and rotation) in the plane orthogonal to the beam propagation direction are spontaneously broken. We use a simple optical feedback scheme [4], where the transmitted pump beam is retro-reflected to the atoms by a high-reflectivity mirror located at a distance d behind the cloud. This feedback loop transforms phase fluctuations of the transmitted wave into intensity fluctuations, which then react on the atomic medium. If the feedback is positive, a transverse instability can develop leading to the spontaneous appa...
Philosophical transactions. Series A, Mathematical, physical, and engineering sciences, 2014
We study non-equilibrium spatial self-organisation in cold atomic gases, where long-range spatial... more We study non-equilibrium spatial self-organisation in cold atomic gases, where long-range spatial order spontaneously emerges from fluctuations in the plane transverse to the propagation axis of a single optical beam. The self-organisation process can be interpreted as a synchronisation transition in a fully connected network of fictitious oscillators, and described in terms of the Kuramoto model. c
ABSTRACT We theoretically, numerically and experimentally investigate spontaneous transverse inst... more ABSTRACT We theoretically, numerically and experimentally investigate spontaneous transverse instabilities in cold atomic gases, arising from the action of dispersive light forces. Previous research focused on pattern-forming instabilities in hot gases where optical nonlinearities arise from the internal structure of the atoms and spatio-temporal structures are encoded in the populations and coherences of the medium. Dipole forces acting on the center-of-mass of laser-cooled atoms, being dependent on gradients of the optical intensity, are also nonlinear in nature: previous studies focused, for instance, on beam filamentation. Here we investigate the situation where a positive feedback loop is present in the system leading to a pattern-forming instability. We stress that the resulting spatial structures are encoded also in the spatial density distribution, effectively leading to the self-assembly of an optical atomic lattice.
Physical Review Letters, 2014
We investigate transverse symmetry-breaking instabilities emerging from the opto-mechanical coupl... more We investigate transverse symmetry-breaking instabilities emerging from the opto-mechanical coupling between light and the translational degrees of freedom of a collisionless, damping-free gas of cold, two-level atoms. We develop a kinetic theory which can also be mapped on to the case of an electron plasma under ponderomotive forces. A general criterion for the existence and spatial scale of transverse instabilities is identified; in particular, we demonstrate that monotonously decreasing velocity distribution functions are always unstable.
Physical Review A, 2011
We suggest and demonstrate a scheme for coherent nonlocal compensation of pure phase objects base... more We suggest and demonstrate a scheme for coherent nonlocal compensation of pure phase objects based on two-photon polarization and momentum entangled states. The insertion of a single phase object on one of the beams reduces the purity of the state and the amount of shared entanglement, whereas the original entanglement can be retrieved by adding a suitable phase object on the other beam. In our setup polarization and momentum entangled states are generated by spontaneous parametric downconversion and then purified using a programmable spatial light modulator, which may be also used to impose arbitrary space dependent phase functions to the beams. As a possible application, we suggest and demonstrate a quantum key distribution protocol based on nonlocal phase compensation.
Physical Review A, 2011
We suggest and demonstrate an all-optical experimental setup to observe and engineer entanglement... more We suggest and demonstrate an all-optical experimental setup to observe and engineer entanglement oscillations of a pair of polarization qubits in a non-Markovian channel. We generate entangled photon pairs by spontaneous parametric downconversion (SPDC), and then insert a programmable spatial light modulator in order to impose a polarization dependent phase-shift on the spatial domain of the SPDC output and to create an effective non-Markovian environment. Modulation of the enviroment spectrum is obtained by inserting a spatial grating on the signal arm. In our experiment, programmable oscillations of entanglement are achieved, with the maximally revived state that violates Bell's inequality by 17 standard deviations.
International Journal of Quantum Information, 2011
We address the estimation of phase-shifts for qubit systems in the presence of noise. Different s... more We address the estimation of phase-shifts for qubit systems in the presence of noise. Different sources of noise are considered including bit flip, bit-phase flip and phase flip. We derive the ultimate quantum limits to precision of estimation by evaluating the analytical expressions of the quantum Fisher information and assess performances of feasible measurements by evaluating the Fisher information for realistic spin-like measurements. We also propose an experimental scheme to test our results.
arXiv (Cornell University), Aug 6, 2013
2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)
The spontaneous emergence of spatiotemporal order is a prominent feature of physical systems driv... more The spontaneous emergence of spatiotemporal order is a prominent feature of physical systems driven far from equilibrium. Recent experimental works have provided paradigmatic examples in transverse nonlinear optics with cold atoms such as spatial (optomechanical) or magnetic ordering [1], [2]. In the first case, the bunching of atoms due to dipole forces provides positive feedback leading to multimode symmetry breaking.
2013 Sixth "Rio De La Plata" Workshop on Laser Dynamics and Nonlinear Photonics, 2013
We discuss the formation of optomechanical structures from the interaction between linear dielect... more We discuss the formation of optomechanical structures from the interaction between linear dielectric scatterers and a light field via dipole forces without the need for optical nonlinearities. The experiment uses a high density sample of Rb atoms in a single mirror feedback geometry. We observe hexagonal structures in the light field and a complementary honeycomb pattern in the atomic density. Different theoretical approaches are discussed assuming either viscous damping of the atomic velocity or not. The interplay between electronic and optomechanical nonlinearities is analyzed. A prediction for dissipative light-matter density solitons is given. The investigations demonstrate novel prospects for the manipulation of matter in a pattern forming system in which quantum effects should be accessible.
Advanced Photonics, 2014
Experimental, theoretical and numerical evidence of optomechanical self-structuring of a laser be... more Experimental, theoretical and numerical evidence of optomechanical self-structuring of a laser beam in a cloud of cold atoms in a single-mirror feedback configuration is presented. Optomechanical dissipative solitons can be encoded in the atomic density.
Nonlinear Optics, 2013
We demonstrate an optomechanical instability in a sample of cold atoms driven by a single laser b... more We demonstrate an optomechanical instability in a sample of cold atoms driven by a single laser beam in presence of a feedback mirror. Hexagonal light filaments propagate in atom-depleted tubes forming a honeycomb lattice.
Optics Express, 2013
We investigate the coupled dynamics of light and cold atoms in a unidirectional ring cavity, in t... more We investigate the coupled dynamics of light and cold atoms in a unidirectional ring cavity, in the regime of low saturation and linear single-atom response. As the dispersive opto-mechanical coupling between light and the motional degrees of freedom of the atoms makes the dynamics nonlinear, we find that localized, nonlinearity-sustained and bistable structures can be encoded in the atomic density by means of appropriate control beams.
Physical Review A, 2012
Transverse pattern formation in an optical cavity containing a cloud of cold two-level atoms is d... more Transverse pattern formation in an optical cavity containing a cloud of cold two-level atoms is discussed. We show that density modulation becomes the dominant mechanism as the atomic temperature is reduced. Indeed, for low but achievable temperatures the internal degrees of freedom of the atoms can be neglected, and the system is well described by treating them as mobile dielectric particles. A linear stability analysis predicts the instability threshold and the spatial scale of the emergent pattern. Numerical simulations in one and two transverse dimensions confirm the instability and predict honeycomb and hexagonal density structures, respectively, for the blue and red detuned cases.
This text may be downloaded only for personal research purposes. Any additional reproduction for ... more This text may be downloaded only for personal research purposes. Any additional reproduction for other purposes, whether in hard copies or electronically, requires the consent of the Florence School of Regulation.
We theoretically investigate the specific heat in the normal state of an ultracold Fermi gas. Usi... more We theoretically investigate the specific heat in the normal state of an ultracold Fermi gas. Using a strong-coupling BCS-BEC crossover theory, we clarify how strong pairing fluctuations affect this quantity in the whole BCS-BEC crossover region. Recently, the specific heat has been measured in the unitarity limit of this system[1], exhibiting a lambda-like temperature dependence near the superfluid phase transition temperature, as opposed to the well-known Tlinear behavior obtained in normal Fermi liquids. We examine whether this anomalous temperature dependence is due to strong pairing fluctuations. We also discuss effects of the socalled pseudogap phenomenon on the specific heat. Since the existence of strong pairing fluctuations is a crucial key in understanding the BCS-BEC crossover physics, our results would be helpful in elucidating their effects on the thermodynamic properties of an ultracold Fermi gas.
Physical Review Letters, 2015
Physical Review B, 2015
We consider a system composed by N atoms trapped within a multimode cavity, whose theoretical des... more We consider a system composed by N atoms trapped within a multimode cavity, whose theoretical description is captured by a disordered multimode Dicke model. We show that in the resonant, zero-field limit the system exactly realizes the Sherrington-Kirkpatrick model. Upon a redefinition of the temperature, the same dynamics is realized in the dispersive, strong-field limit. This regime also gives access to spin-glass observables which can be used to detect replica symmetry breaking.
form only given. Spontaneous optical pattern formation occurs in a variety of nonlinear systems [... more form only given. Spontaneous optical pattern formation occurs in a variety of nonlinear systems [1], including hot atomic vapors [2]. On the other hand, the spatial self-organization of atomic ensembles due to opto-mechanical coupling has received a lot of interest in recent years [3].We report on the observation of transverse self-organization of a cold atomic cloud (issued from a magnetooptical trap) under the action of a single pump laser beam. Two symmetries (translation and rotation) in the plane orthogonal to the beam propagation direction are spontaneously broken. We use a simple optical feedback scheme [4], where the transmitted pump beam is retro-reflected to the atoms by a high-reflectivity mirror located at a distance d behind the cloud. This feedback loop transforms phase fluctuations of the transmitted wave into intensity fluctuations, which then react on the atomic medium. If the feedback is positive, a transverse instability can develop leading to the spontaneous appa...
Philosophical transactions. Series A, Mathematical, physical, and engineering sciences, 2014
We study non-equilibrium spatial self-organisation in cold atomic gases, where long-range spatial... more We study non-equilibrium spatial self-organisation in cold atomic gases, where long-range spatial order spontaneously emerges from fluctuations in the plane transverse to the propagation axis of a single optical beam. The self-organisation process can be interpreted as a synchronisation transition in a fully connected network of fictitious oscillators, and described in terms of the Kuramoto model. c
ABSTRACT We theoretically, numerically and experimentally investigate spontaneous transverse inst... more ABSTRACT We theoretically, numerically and experimentally investigate spontaneous transverse instabilities in cold atomic gases, arising from the action of dispersive light forces. Previous research focused on pattern-forming instabilities in hot gases where optical nonlinearities arise from the internal structure of the atoms and spatio-temporal structures are encoded in the populations and coherences of the medium. Dipole forces acting on the center-of-mass of laser-cooled atoms, being dependent on gradients of the optical intensity, are also nonlinear in nature: previous studies focused, for instance, on beam filamentation. Here we investigate the situation where a positive feedback loop is present in the system leading to a pattern-forming instability. We stress that the resulting spatial structures are encoded also in the spatial density distribution, effectively leading to the self-assembly of an optical atomic lattice.
Physical Review Letters, 2014
We investigate transverse symmetry-breaking instabilities emerging from the opto-mechanical coupl... more We investigate transverse symmetry-breaking instabilities emerging from the opto-mechanical coupling between light and the translational degrees of freedom of a collisionless, damping-free gas of cold, two-level atoms. We develop a kinetic theory which can also be mapped on to the case of an electron plasma under ponderomotive forces. A general criterion for the existence and spatial scale of transverse instabilities is identified; in particular, we demonstrate that monotonously decreasing velocity distribution functions are always unstable.
Physical Review A, 2011
We suggest and demonstrate a scheme for coherent nonlocal compensation of pure phase objects base... more We suggest and demonstrate a scheme for coherent nonlocal compensation of pure phase objects based on two-photon polarization and momentum entangled states. The insertion of a single phase object on one of the beams reduces the purity of the state and the amount of shared entanglement, whereas the original entanglement can be retrieved by adding a suitable phase object on the other beam. In our setup polarization and momentum entangled states are generated by spontaneous parametric downconversion and then purified using a programmable spatial light modulator, which may be also used to impose arbitrary space dependent phase functions to the beams. As a possible application, we suggest and demonstrate a quantum key distribution protocol based on nonlocal phase compensation.
Physical Review A, 2011
We suggest and demonstrate an all-optical experimental setup to observe and engineer entanglement... more We suggest and demonstrate an all-optical experimental setup to observe and engineer entanglement oscillations of a pair of polarization qubits in a non-Markovian channel. We generate entangled photon pairs by spontaneous parametric downconversion (SPDC), and then insert a programmable spatial light modulator in order to impose a polarization dependent phase-shift on the spatial domain of the SPDC output and to create an effective non-Markovian environment. Modulation of the enviroment spectrum is obtained by inserting a spatial grating on the signal arm. In our experiment, programmable oscillations of entanglement are achieved, with the maximally revived state that violates Bell's inequality by 17 standard deviations.
International Journal of Quantum Information, 2011
We address the estimation of phase-shifts for qubit systems in the presence of noise. Different s... more We address the estimation of phase-shifts for qubit systems in the presence of noise. Different sources of noise are considered including bit flip, bit-phase flip and phase flip. We derive the ultimate quantum limits to precision of estimation by evaluating the analytical expressions of the quantum Fisher information and assess performances of feasible measurements by evaluating the Fisher information for realistic spin-like measurements. We also propose an experimental scheme to test our results.