Sandro Stringari

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Sandro Stringari
Born (1949-03-02) March 2, 1949 (age 73)
Nationality Italian
Alma mater University of Pisa and Scuola Normale Superiore
Scientific career
Fields Theoretical physics, Nuclear physics, and Ultracold atoms
Institutions University of Trento
Academic advisors Bruno Touschek, Renzo Leonardi and David Brink

Sandro Stringari is an Italian theoretical physicist, who has contributed to the theory of quantum many-body physics, including atomic nuclei, quantum liquids and ultra-cold atomic Bose and Fermi gases. He has developed in a systematic way the sum rule approach to the collective behavior of interacting systems.

Contents

Biography

After the studies at the University of Pisa and at the Scuola Normale Superiore Pisa, completed in 1972 and supervised by Bruno Touschek, he moved to Trento and Oxford under the supervision of Renzo Leonardi and David Brink, respectively. In the years 1978/79 and 1985/86, invited by Oriol Bohigas Marti, he has worked at the Institut de Physique Nucleaire in Orsay. In 1990 he became full professor at the University of Trento, where he currently teaches an undergraduate course on quantum mechanics and a graduate course on quantum gases and superfluidity. [1] In 2002 he established in Trento the Center on Bose –Einstein Condensation (BEC Center), founded by the Istituto Nazionale per la Fisica della Materia (INFM), and now part of CNR. In the year 2004/2005, invited by Claude Cohen-Tannoudji, he held the European Chair at the Collège de France, in Paris. In 2010 he was recipient of the 5 years ERC Advanced Grant “Quantum Gases beyond equilibrium”. Since 2011 he is corresponding member of the Accademia Nazionale dei Lincei.

Main scientific contributions

In the first period of his scientific career Sandro Stringari focused on the magnetic properties of atomic nuclei and on the isospin degree of freedom, developing the innovative sum rule approach to the collective excitations. [2]

Starting from the 80’s he oriented his interests in the direction of atomic clusters and quantum liquids. Major contributions of this period are the study of the evaporation mechanism of helium clusters [3] and the T=0 extension of the Hohenberg-Mermin-Wagner theorem. [4]

His interests in the physics of Bose-Einstein condensates (BEC) started with the workshop on Bose-Einstein Condensation (BEC), known as the “Levico conference”, organized in 1993 at Levico. [5] After the first experimental realization of BEC in 1995, he developed the formalism of superfluid hydrodynamics to describe the collective oscillations of a harmonically trapped BECs, providing analytic predictions for their frequencies. [6] This contribution had a major impact on the first generation of experiments on ultra cold quantum gases and influenced an important line of theoretical work. Later contributions to the dynamics of trapped quantum gases, and to their rotational, superfluid and thermodynamic properties are summarized in the review papers on Bose-Einstein condensates [7] and Fermi gases [8] as well as in the book on Bose-Einstein Condensation and Superfluidity [9] written in collaboration with Lev Pitaevskii. For a complete description of his main scientific achievements see bec.science.unitn.it

Related Research Articles

Bose–Einstein condensate State of matter

In condensed matter physics, a Bose–Einstein condensate (BEC) is a state of matter that is typically formed when a gas of bosons at low densities is cooled to temperatures very close to absolute zero. Under such conditions, a large fraction of bosons occupy the lowest quantum state, at which point microscopic quantum mechanical phenomena, particularly wavefunction interference, become apparent macroscopically. A BEC is formed by cooling a gas of extremely low density to ultra-low temperatures.

Supersolid State of matter

In condensed matter physics, a supersolid is a spatially ordered material with superfluid properties. In the case of helium-4, it has been conjectured since the 1960s that it might be possible to create a supersolid. Starting from 2017, a definitive proof for the existence of this state was provided by several experiments using atomic Bose–Einstein condensates. The general conditions required for supersolidity to emerge in a certain substance are a topic of ongoing research.

Fermionic condensate State of matter

A fermionic condensate or Fermi–Dirac condensate is a superfluid phase formed by fermionic particles at low temperatures. It is closely related to the Bose–Einstein condensate, a superfluid phase formed by bosonic atoms under similar conditions. The earliest recognized fermionic condensate described the state of electrons in a superconductor; the physics of other examples including recent work with fermionic atoms is analogous. The first atomic fermionic condensate was created by a team led by Deborah S. Jin in 2003.

Wolfgang Ketterle German physicist

Wolfgang Ketterle is a German physicist and professor of physics at the Massachusetts Institute of Technology (MIT). His research has focused on experiments that trap and cool atoms to temperatures close to absolute zero, and he led one of the first groups to realize Bose–Einstein condensation in these systems in 1995. For this achievement, as well as early fundamental studies of condensates, he was awarded the Nobel Prize in Physics in 2001, together with Eric Allin Cornell and Carl Wieman.

Hendricus Theodorus Christiaan "Henk" Stoof is a professor in theoretical physics at Utrecht University in the Netherlands. His main interests are atomic physics, condensed matter physics and many-body physics. He is a Fellow of the American Physical Society.

Rudolf Grimm

Rudolf Grimm is an experimental physicist from Austria. His work centres on ultracold atoms and quantum gases. He was the first scientist worldwide who, with his team, succeeded in realizing a Bose–Einstein condensation of molecules.

Ultracold atoms are atoms that are maintained at temperatures close to 0 kelvin, typically below several tens of microkelvin (µK). At these temperatures the atom's quantum-mechanical properties become important.

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David Ceperley

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In physics, Bose–Einstein correlations are correlations between identical bosons. They have important applications in astronomy, optics, particle and nuclear physics.

Superstripes is a generic name for a phase with spatial broken symmetry that favors the onset of superconducting or superfluid quantum order. This scenario emerged in the 1990s when non-homogeneous metallic heterostructures at the atomic limit with a broken spatial symmetry have been found to favor superconductivity. Before a broken spatial symmetry was expected to compete and suppress the superconducting order. The driving mechanism for the amplification of the superconductivity critical temperature in superstripes matter has been proposed to be the shape resonance in the energy gap parameters ∆n that is a type of Fano resonance for coexisting condensates.

Robert Seiringer

Robert Seiringer is an Austrian mathematical physicist.

Superfluidity State of matter

Superfluidity is the characteristic property of a fluid with zero viscosity which therefore flows without any loss of kinetic energy. When stirred, a superfluid forms vortices that continue to rotate indefinitely. Superfluidity occurs in two isotopes of helium when they are liquefied by cooling to cryogenic temperatures. It is also a property of various other exotic states of matter theorized to exist in astrophysics, high-energy physics, and theories of quantum gravity. The theory of superfluidity was developed by Soviet theoretical physicists Lev Landau and Isaak Khalatnikov.

Immanuel Bloch is a German experimental physicist. His research is focused on the investigation of quantum many-body systems using ultracold atomic and molecular quantum gases. Bloch is known for his work on ultracold atoms in artificial crystals of light, so called optical lattices and especially the first realization of a quantum phase transition from a weakly interacting superfluid to a strongly interacting Mott insulating state of matter.

Tilman Esslinger German physicist

Tilman Esslinger is a German experimental physicist. He is Professor at ETH Zurich, Switzerland, and works in the field of ultracold quantum gases and optical lattices.

Scissors Modes Collective excitations

Scissors Modes are collective excitations in which two particle systems move with respect to each other conserving their shape. For the first time they were predicted to occur in deformed atomic nuclei by N. LoIudice and F. Palumbo, who used a semiclassical Two Rotor Model, whose solution required a realization of the O(4) algebra that was not known in mathematics. In this model protons and neutrons were assumed to form two interacting rotors to be identified with the blades of scissors. Their relative motion (Fig.1) generates a magnetic dipole moment whose coupling with the electromagnetic field provides the signature of the mode.

Lev Petrovich Pitaevskii is a Russian theoretical physicist, who made contributions to the theory of quantum mechanics, electrodynamics, low-temperature physics, plasma physics, and condensed matter physics. Together with Evgeny Lifshitz and Vladimir Berestetskii, Lev Pitaevskii has also been the co-author of a few volumes of the influential Landau–Lifschitz Course of Theoretical Physics series. His academic status is professor.

Bose–Einstein condensation can occur in quasiparticles, particles that are effective descriptions of collective excitations in materials. Some have integer spins and can be expected to obey Bose–Einstein statistics like traditional particles. Conditions for condensation of various quasiparticles have been predicted and observed. The topic continues to be an active field of study.

Bose–Einstein condensation of polaritons is a growing field in semiconductor optics research, which exhibits spontaneous coherence similar to a laser, but through a different mechanism. A continuous transition from polariton condensation to lasing can be made similar to that of the crossover from a Bose–Einstein condensate to a BCS state in the context of Fermi gases. Polariton condensation is sometimes called “lasing without inversion”.

References

  1. "UniTrento - Sandro Stringari - Teaching" . Retrieved 24 February 2019.
  2. Lipparini, E.; Stringari, S. (1989). "Sum rules and giant resonances in nuclei". Physics Reports. Elsevier BV. 175 (3–4): 103–261. Bibcode:1989PhR...175..103L. doi:10.1016/0370-1573(89)90029-x. ISSN   0370-1573.
  3. Brink, D. M.; Stringari, S. (1990). "Density of states and evaporation rate of helium clusters". Zeitschrift für Physik D. Springer Science and Business Media LLC. 15 (3): 257–263. Bibcode:1990ZPhyD..15..257B. doi:10.1007/bf01437187. ISSN   0178-7683. S2CID   84178148.
  4. Pitaevskii, L.; Stringari, S. (1991). "Uncertainty principle, quantum fluctuations, and broken symmetries". Journal of Low Temperature Physics. Springer Science and Business Media LLC. 85 (5–6): 377–388. Bibcode:1991JLTP...85..377P. doi:10.1007/bf00682193. ISSN   0022-2291. S2CID   121848601.
  5. Bose Einstein Condensation Proceedings of the 1993 Levico International Workshop, A. Griffin, D. Snoke and S. Stringari eds. (Cambridge University Press, 1995)
  6. Stringari, S. (1996-09-16). "Collective Excitations of a Trapped Bose-Condensed Gas". Physical Review Letters. American Physical Society (APS). 77 (12): 2360–2363. arXiv: cond-mat/9603126 . Bibcode:1996PhRvL..77.2360S. doi:10.1103/physrevlett.77.2360. ISSN   0031-9007. PMID   10061934. S2CID   981505.
  7. Dalfovo, Franco; Giorgini, Stefano; Pitaevskii, Lev P.; Stringari, Sandro (1999-04-01). "Theory of Bose-Einstein condensation in trapped gases". Reviews of Modern Physics. American Physical Society (APS). 71 (3): 463–512. arXiv: cond-mat/9806038 . Bibcode:1999RvMP...71..463D. doi:10.1103/revmodphys.71.463. ISSN   0034-6861. S2CID   55787701.
  8. Giorgini, Stefano; Pitaevskii, Lev P.; Stringari, Sandro (2008-10-02). "Theory of ultracold atomic Fermi gases". Reviews of Modern Physics. American Physical Society (APS). 80 (4): 1215–1274. arXiv: 0706.3360 . Bibcode:2008RvMP...80.1215G. doi:10.1103/revmodphys.80.1215. ISSN   0034-6861. S2CID   117755089.
  9. Bose-Einstein Condensation and Superfluidity
    Lev Pitaevskii and Sandro Stringari, , Int. Series of Monographs on Physics (Bose-Einstein Condensation and Superfluidity. Oxford University Press. 2016. p. 576. ISBN   9780198758884.)