Seminars



Wednesday, 21 December, 2016 - 14:30 - 15:30
Aula Grassano

Simone Bacchio (University of Cyprus, Cyprus)

title:  "Multigrid preconditioning for Lattice QCD"  




Wednesday, 18 January, 2017 - 14:00 - 15:00
Aula Grassano

Stefano Scopel (Sogang University, Seoul, South Korea).

Title: "Toward a model-independent interpretation of Dark Matter

direct detection data"




Wednesday, 15 February, 2017 - 14:00 - 15:00
Aula Grassano

Johan Blåbäck (Institut de Physique Théorique, CEA Saclay , France)

title  "Boundaries of the classical de Sitter landscape"  




Friday, 17 February, 2017 - 14:30 - 15:30
Sala Struttura della Materia

 

 

Dr. Basile Gallet De Saint Aurin

SPEC, CEA Saclay (France)

“Energy dissipation in rotating turbulence”

Abstract

Rapidly rotating turbulence is present in many different contexts, ranging from industrial flows to atmospheric and oceanic motions. In these situations, the turbulent energy dissipation rate is a key quantity: engineers want to optimize the power efficiency, while oceanographers and climate scientists want to parametrize turbulent energy dissipation in the ocean-atmosphere coupled system. Finally, the dissipated power is the central quantity of the Obukhov-Kolmogorov theory of turbulence.

I will present two experiments aimed at studying the influence of global rotation on the energy dissipation rate: does the turbulent flow present a dissipation anomaly, like 3D turbulence, or does it dissipate energy at a laminar rate, like 2D turbulent flows? How is the drag coefficient of a moving object affected by global rotation?

This experimental work is supplemented by recent theoretical progress proving that a large class of rotating flows becomes exactly two-dimensional at low Rossby number, with no energy dissipation anomaly. 




Wednesday, 22 February, 2017 - 11:00 - 13:00
Aula U. Grassano- Dipartimento di Fisica



Monday, 27 February, 2017 - 14:30 - 15:30
Aula Grassano

Rubik Poghossian (Yerevan Physics Institute, Armenia)

itle:" The duality between 4d SYM in Nekrasov Shatashvili limit and the semi-classical 2d CFT"



 




Wednesday, 1 March, 2017 - 14:30 - 15:30
Aula Grassano

Enrico Rinaldi (RIKEN-BNL Center, Brookhaven National Laboratory, United States)

title:  "Beyond the Standard Model Physics with Lattice Simulations"  




Monday, 6 March, 2017 - 14:30 - 15:30
Aula Grassano

 Raffaele Savelli (IFT/UAM - Madrid  )

title:  "A T-brane's tale"  




Monday, 13 March, 2017 - 14:30 - 15:30
Aula Grassano

Andrea Morales ('Institute for Quantum Eletronics ETH, Zurich)

 title: "Continuous and discrete supersolidity with ultracold atoms in optical cavities"Abstract:  The realization of a ‘supersolid' state of matter, simultaneously featuring frictionless flow and crystalline order has been a long standing goal in condensed matter physics. This quantum state requires the breaking of two continuous symmetries, the phase invariance of the superfluid and the continuous translational invariance to form the crystal. Since its first proposal for Helium almost 50 years ago, experimental verification of supersolidity remained elusive. A variant with only discrete translational symmetry breaking on a pre-imposed lattice structure, the ‘lattice supersolid’, has been realized based on self-organization of a Bose-Einstein condensate (BEC) in an optical cavity. However, lattice supersolids do not feature the high ground state degeneracy that characterizes the supersolid state as originally proposed. We realize such phase by coupling a BEC to the modes of two optical cavities crossing at an angle of 60°. We pump the homogeneous BEC with a laser beam far detuned from the atomic resonance but close to the cavity resonances. Upon a certain threshold power of the pump laser the light occupation in the cavities becomes non zero and a phase transition occurs. At the phase transition, the atomic profile ‘crystallize’ by acquiring a density modulation that can form continuously in space due to scattering of the pump light in the cavity modes. Changing the relative cavity detunings from the pump beam we can tune the symmetry of the system from U(1) to Z(2), therefore allowing the independent realization of a supersolid or a lattice-supersolid. Additionally using cavity-enhanced Bragg spectroscopy we probe the excitation spectrum of the supersolid across its phase transition and we map out a Higgs and a Goldstone pair. Due to the finite decay of the intra-cavity light field we can also monitor the evolution of these modes in real time.