A5040109807- Cold Atom Physics and Bose-Einstein Condensates
- Quantum Mechanics and Applications
- Mechanical and Optical Resonators
- Quantum, superfluid, helium dynamics
- Quantum Electrodynamics and Casimir Effect
- Atomic and Subatomic Physics Research
- Quantum Information and Cryptography
- Cosmology and Gravitation Theories
- Advanced Thermodynamics and Statistical Mechanics
- Advanced Frequency and Time Standards
- Experimental and Theoretical Physics Studies
- Dark Matter and Cosmic Phenomena
- Particle physics theoretical and experimental studies
- Pulsars and Gravitational Waves Research
- Magnetic confinement fusion research
- Noncommutative and Quantum Gravity Theories
- Atomic and Molecular Physics
- Force Microscopy Techniques and Applications
- Spectroscopy and Quantum Chemical Studies
- Black Holes and Theoretical Physics
- Laser-Plasma Interactions and Diagnostics
- Quantum chaos and dynamical systems
- Scientific Measurement and Uncertainty Evaluation
- Thermal Radiation and Cooling Technologies
- Quantum optics and atomic interactions
Dartmouth College
2009-2024
University of Padua
2013-2022
Hospital de Clínicas da Unicamp
2016
Center for Astrophysics Harvard & Smithsonian
2010-2015
University of Massachusetts Boston
2011
Istituto Nazionale di Fisica Nucleare, Sezione di Padova
1994-2006
Los Alamos National Laboratory
2002-2004
Istituto Nazionale per la Fisica della Materia
2002-2004
Sapienza University of Rome
1987-2003
Istituto Nazionale di Fisica Nucleare, Sezione di Roma I
1990-2002
We report on the measurement of Casimir force between conducting surfaces in a parallel configuration. The is exerted silicon cantilever coated with chromium and similar rigid surface detected by looking at shifts induced frequency when latter approached. scaling distance was tested 0.5-3.0 microm range, related coefficient determined 15% precision level.
We have studied dissipation in a Bose--Einstein condensed gas by moving blue detuned laser beam through the condensate at different velocities. Strong heating was observed only above critical velocity.
We have studied the hydrodynamic flow in a Bose-Einstein condensate stirred by macroscopic object, blue-detuned laser beam, using nondestructive situ phase contrast imaging. A critical velocity for onset of pressure gradient has been observed, and shown to be density dependent. The technique compared calorimetric method used previously measure heating induced motion beam.
Several high-precision physics experiments are approaching a level of sensitivity at which the intrinsic quantum nature experimental apparatus is dominant source fluctuations limiting measurements. This limit embodied by Heisenberg uncertainty principle, prohibits arbitrarily precise simultaneous measurements two conjugate observables system but allows one-time single observable with any precision. The dynamical evolution immediately following measurement limits class that may be measured...
We review the status of cooling techniques aimed at achieving deepest quantum degeneracy for atomic Fermi gases. first discuss some physical motivations, providing a quantitative assessment need deep in relevant physics cases, such as search unconventional superfluid states. Attention is then focused on most widespread technique to reach systems, sympathetic Bose-Fermi mixtures, organizing discussion according specific species involved. Various proposals circumvent limitations degeneracy,...
We have performed precision electrostatic calibrations in the sphere-plane geometry and observed anomalous behavior. Namely, scaling exponent of signal with distance was found to be smaller than expected on basis pure Coulombian contribution residual potential dependent. argue that these findings affect accuracy invite reanalysis previous determinations Casimir force.
The Casimir force is the ultimate background in ongoing searches of extra-gravitational forces micrometer range. Eccentric cylinders offer favorable experimental conditions for such measurements as spurious gravitational and electrostatic effects can be minimized. Here we report on evaluation exact interaction between perfectly conducting eccentric using a mode summation technique, study different limiting cases relevance measurements, with potential implications understanding mechanical...
Free fall in a uniform gravitational field is reexamined the case of quantum states with and without classical analogue. The interplay between kinematics dynamics evolution falling test particle discussed allowing for better understanding equivalence principle at operational level.
We report on a proposal aimed at measuring the Casimir force in cylinder-plane configuration. The is evaluated including corrections due to finite parallelism, conductivity, and temperature. range of validity proximity approximation also discussed. An apparatus test feasibility precision measurement this configuration has been developed, we describe both procedure control parallelism results electrostatic calibration. Finally discuss possibility thermal contribution deviations from...
We propose an experiment for generating and detecting vacuum-induced dissipative motion. A high frequency mechanical resonator driven in resonance is expected to dissipate energy quantum vacuum via photon emission. The photons are stored a quality electromagnetic cavity detected through their interaction with ultracold alkali-metal atoms prepared inverted population of hyperfine states. Superradiant amplification the generated results detectable radio-frequency signal temporally...
Surface modes in a Bose-Einstein condensate of sodium atoms have been studied. We observed excitations standing and rotating quadrupolar hexadecapolar modes. The were excited with high spatial temporal resolution using the optical dipole force rapidly scanning laser beam. This novel technique is very flexible should be useful for study condensates vortices.
The search for non-relativistic deviations from Newtonian gravitation can lead to new phenomena signalling the unification of gravity with other fundamental interactions. Various recent theoretical frameworks indicate a possible window non-Newtonian forces gravitational coupling strength in micrometre range. major expected background same range is attributable Casimir force or variants it if dielectric materials, rather than conducting ones, are considered. Here we review measurements...
We conjecture that weak interactions are peculiar manifestations of quantum gravity at the Fermi scale, and constant is related to Newtonian gravitation. In this framework one may understand violations fundamental symmetries by interactions, in particular parity violations, as due fluctuations spacetime geometry a Planck scale coinciding with scale. As consequence, gravitational phenomena should play more important role microworld, experimental settings suggested test hypothesis.
We discuss fast frictionless cooling techniques in the framework of sympathetic cold atomic mixtures. It is argued that optimal an species - which deepest quantum degeneracy regime achieved may be obtained by means with another whose trapping frequency dynamically changed to maintain constancy Lewis-Riesenfeld adiabatic invariant. Advantages and limitations this strategy are discussed, particular regard possibility Fermi gases a deeper degenerate regime.
We show how the "proton radius puzzle" emerging from measurement of Lamb shift in muonic hydrogen may be solved by means a binding energy contribution due to an effective Yukawian gravitational potential related charged weak interactions. The residual discrepancy experimental result should mainly attributable need for determination proton. absence analogous electronic imply existence generation-dependent interactions, corroborating previous proposals. Muonic plays crucial role test possible...
We describe the principle and status of PVLAS experiment which is being assembled at INFN Laboratori Nazionali di Legnaro (Legnaro, Padua, Italy) to look for coherent effects, related QED vacuum structure, on propagation a polarized light beam in strong magnetic field.
We discuss a proposal to measure the Casimir force in parallel plate configuration $1-10μ$m range via high-sensitivity torsional balance. This will allow thermal contribution therefore discriminating between various approaches discussed so far. The accurate control of this distances is also required improve limits existence non-Newtonian forces micrometer predicted by unification models fundamental interactions.
We report on measurements performed an apparatus aimed to study the Casimir force in cylinder-plane configuration. The electrostatic calibrations evidence anomalous behaviors dependence of and minimizing potential upon distance. discuss analogies differences these anomalies with respect those already observed sphere-plane At smallest explored distances we observe frequency shifts non-Coulombian nature preventing measurement same range. also parallel plane configuration, showing that distance...
We discuss conditions for the enhancement of fusion reactivities arising from different choices energy distribution functions reactants. The key element potential gains in reactivity is identified functional dependence tunnellng coefficient upon energy, ensuring existence a finite range temperatures which processes boosted with respect to Maxwellian case. This shown, using convenient parameterization tunneling analytically simplified case bimodal Maxwell-Boltzmann distribution, and...
We consider the Casimir interaction between a cylinder and hollow cylinder, both conducting, with parallel axis slightly different radii. The force, which vanishes in coaxial situation, is evaluated for small large eccentricities using proximity approximation. cylindrical configuration offers various experimental advantages respect to planes or plane-sphere geometries, leading favourable conditions search of extra-gravitational forces micrometer range observation finite-temperature corrections.
In a recent Comment, Decca et al. [Phys. Rev. A 79, 026101 (2009)] discussed the origin of anomalies recently reported by us in Phys. 78, 036102(R) (2008). Here we restate our view corroborated their considerations that quantitative geometrical and electrostatic characterizations conducting surfaces (a topic not explicitly literature until very recently) are critical for assessment precision accuracy demonstration Casimir force deriving meaningful limits on existence Yukawian components...
Collisions between electrically charged particles and neutral atoms are central for understanding the dynamics of gases plasmas in a variety physical situaziones terrestrial astronomical interest. Specifically, redistribution angular momentum states within degenerate shell highly excited Rydberg occurs efficiently distant collisions with ions. This process is crucial establishing validity local thermal equilibrium assumption may also play role determining precise ionization fraction...