BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Ensemble inequivalence for systems with long-range interactions - 
 Prof. Stefano Ruffo
DTSTART:20260512T100000Z
DTEND:20260512T110000Z
UID:TALK245227@talks.cam.ac.uk
CONTACT:Pietro Lio
DESCRIPTION:Systems governed by short-range forces—such as gases or simp
 le magnets—obey the property of additivity\, where the total energy is s
 imply the sum of the energies of its macroscopic components. In contrast\,
  systems with long-range interactions (LRI)\, characterized by an inter-pa
 rticle potential decaying as $V(r) \\sim 1/r^\\alpha$ (where $\\alpha \\le
  d$)\, are non-additive. A striking consequence of this non-additivity is 
 ensemble inequivalence\, in which the microcanonical (fixed energy $E$) an
 d canonical (fixed temperature $T$) ensembles yield divergent physical pre
 dictions. Key phenomena associated with LRI include negative specific heat
 \, temperature jumps at phase transitions\, and the emergence of quasi-sta
 tionary states. I will demonstrate these features by discussing classical 
 spin models\, such as the Nagle-Kardar spin-1/2 model with competing mean-
 field and nearest-neighbor interactions\, as well as the quantum Lipkin-Me
 shkov-Glick model augmented with multi-spin interactions.
LOCATION:Venue to be confirmed
END:VEVENT
END:VCALENDAR