Quantum Initiative: Quantum Lunch

The Quantum Lunch is regularly held on Thursdays in the Theoretical Division Conference Room, TA-3, Building 123, Room 121.

The organizing committee includes Malcolm Boshier (P-21), Lukasz Cincio (T-4), Diego Dalvit (T-4), Changhyun Ryu (P-21) , Nikolai Sinitsyn (T-4), Rolando Somma (T-4), Yigit Subasi (T-4), Christopher Ticknor (T-1), and Wojciech Zurek (T-4).

For more information, or to nominate a speaker, contact Yigit Subasi or Lukasz Cincio.

To add your name to the Quantum Lunch email list, contact Kacy Hopwood.

Thursday, April 5, 2018
12:30 PM - 2:00 PM

Speaker: Monique Combescot (Institut des NanoSciences de Paris)

Technical Host: Aurelia Chenu

TOPIC: Composite bosons and their many-body physics

Abstract
A many-body formalism appropriate to describe composite bosons exists for a decade only. The difficulty has been to handle the particles as entities while treating the Pauli exclusion principle between their fermionic constituents in an exact way. This cannot be done through Green functions - which are scalar - but requires an operator algebra based on commutators: four commutators are necessary and sufficient to properly describe the physics of two-fermion particles. The major breakthrough revealed by this formalism is the existence of a many-body interaction induced by fermion exchange, which is missed by all effective Hamiltonians because it is dimensionless. Shiva diagrams have been proposed to visualize these exchanges and calculate composite boson many-body effects in a transparent way. Extension to composite fermions and the associated Kali diagrams will also be presented. Originally designed for semiconductor excitons and non-linear optical effects, this formalism has already proved useful in other fields like cold atomic gases and quantum information, with major hopes for the composite fermion part, in the physics of quarks and the possible quantum discussions between "Alice, Bob and Clara".