Sandro Stringari

Last updated
Sandro Stringari
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, 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.

Related Research Articles

<span class="mw-page-title-main">Bose–Einstein condensate</span> 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 very 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 microscopic quantum-mechanical phenomena, particularly wavefunction interference, become apparent macroscopically. More generally, condensation refers to the appearance of macroscopic occupation of one or several states: for example, in BCS theory, a superconductor is a condensate of Cooper pairs. As such, condensation can be associated with phase transition, and the macroscopic occupation of the state is the order parameter.

<span class="mw-page-title-main">Supersolid</span> 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.

<span class="mw-page-title-main">Wolfgang Ketterle</span> 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.

In condensed matter physics, an ultracold atom is an atom with a temperature near absolute zero. At such temperatures, an atom's quantum-mechanical properties become important.

The Gross–Pitaevskii equation describes the ground state of a quantum system of identical bosons using the Hartree–Fock approximation and the pseudopotential interaction model.

<span class="mw-page-title-main">Jook Walraven</span> Dutch experimental physicist

Joannes Theodorus Maria (Jook) Walraven is a Dutch experimental physicist at the Van der Waals-Zeeman Institute for experimental physics at the University of Amsterdam. From 1967 he studied physics at the University of Amsterdam. Both his doctoral research and PhD research was with Isaac Silvera, on the subject of Bose-Einstein Condensation. Because of the difficulty of his research subject, his promotion took six years instead of four. The aim of his PhD research was to make a gas of atomic hydrogen, which could become the world's first quantum gas. This might then be a suitable candidate for a Bose-Einstein Condensate (BEC).

Atomtronics Atomtronics is the emerging quantum technology of matter-wave circuits which coherently guide propagating ultra-cold atoms. The systems typically include components analogous to those found in electronic, quantum electronics or optical systems, such as beam splitter, transistors, atomic counterpart of Superconducting Quantum Interference Devices (SQUIDs). Applications range from studies of fundamental physics to the development of practical devices.

<span class="mw-page-title-main">David Ceperley</span> American theoretical physicist (born 1949)

David Matthew Ceperley is a theoretical physicist in the physics department at the University of Illinois Urbana-Champaign or UIUC. He is a world expert in the area of Quantum Monte Carlo computations, a method of calculation that is generally recognised to provide accurate quantitative results for many-body problems described by quantum mechanics.

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.

<span class="mw-page-title-main">Robert Seiringer</span> Austrian physicist

Robert Seiringer is an Austrian mathematical physicist.

<span class="mw-page-title-main">Superfluidity</span> Fluid which flows without losing kinetic energy

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 atoms in artificial crystals of light, optical lattices, especially the first realization of a quantum phase transition from a weakly interacting superfluid to a strongly interacting Mott insulating state of matter.

<span class="mw-page-title-main">Tilman Esslinger</span> 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.

<span class="mw-page-title-main">Scissors Modes</span> 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 was 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 his PhD supervisor Evgeny Lifshitz and with Vladimir Berestetskii, he was also the co-author of a few volumes of the influential Landau–Lifschitz Course of Theoretical Physics series. His academic status was 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”.

Randall Gardner Hulet is an American physicist.

In condensed matter physics, the quantum dimer magnet state is one in which quantum spins in a magnetic structure entangle to form a singlet state. These entangled spins act as bosons and their excited states (triplons) can undergo Bose-Einstein condensation (BEC). The quantum dimer system was originally proposed by Matsubara and Matsuda as a mapping of the lattice Bose gas to the quantum antiferromagnet. Quantum dimer magnets are often confused as valence bond solids; however, a valence bond solid requires the breaking of translational symmetry and the dimerizing of spins. In contrast, quantum dimer magnets exist in crystal structures where the translational symmetry is inherently broken. There are two types of quantum dimer models: the XXZ model and the weakly-coupled dimer model. The main difference is the regime in which BEC can occur. For the XXZ model, the BEC occurs upon cooling without a magnetic field and manifests itself as a symmetric dome in the field versus temperature phase diagram centered about H = 0. The weakly-coupled dimer model does not magnetically order in zero magnetic field, but instead orders upon the closing of the spin gap, where the BEC regime begins and is a dome centered at non-zero field.

Benjamin Leonard Lev is an American physicist and Professor of Physics and Applied Physics at Stanford University. He studies quantum many-body physics, both in and out of equilibrium, by combining the tools of ultracold atomic physics, quantum optics, and condensed matter physics.

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. 175 (3–4). Elsevier BV: 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. 15 (3). Springer Science and Business Media LLC: 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. 85 (5–6). Springer Science and Business Media LLC: 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. 77 (12). American Physical Society (APS): 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. 71 (3). American Physical Society (APS): 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. 80 (4). American Physical Society (APS): 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.)