Found 3 result(s)

31.10.2013 (Thursday)

How many is different? Answer from ideal Bose gas

Regular Seminar Jeong-Hyuck Park (Sogang U.)

14:00 QMW
room lecture theatre

How many H2O molecules are needed to form water? While the precise answer is not known, it is clear that the answer should be a finite number rather than infinity. We revisit with care the ideal Bose gas confined in a cubic box which is discussed in most statistical physics textbooks. We show that the isobar of the ideal gas zigzags on the temperature-volume plane featuring a `boiling-like' discrete phase transition, provided the number of particles is equal to or greater than a particular value: 7616. This demonstrates for the first time how a finite system can feature a mathematical singularity and realize the notion of `Emergence', without resorting to the thermodynamic limit. ref: arXiv:1310.5580

08.05.2013 (Wednesday)

Unification of Type IIA and IIB Supergravities

Regular Seminar Jeong-Hyuck Park (Sogang University Seoul and DAMTP Cambridge)

13:15 KCL
room S4.23

To the full order in fermions, we construct D = 10 type II supersymmetric double field theory. We spell the precise N = 2 supersymmetry transformation rules as for 32 supercharges. In terms of a stringy differential geometry beyond Riemann, the constructed action unifies type IIA and IIB supergravities in a manifestly covariant manner with respect to O(10, 10) T-duality and a ‘pair’ of local Lorentz groups, or Spin(1, 9) × Spin(9, 1), besides the usual general covariance of supergravities or the generalized diffeomorphism. The distinction of IIA and IIB may arise after a diagonal gauge fixing of the Lorentz groups. They are identified as two different types of ‘solutions’ rather than two different theories. References: arXiv:1210.5078 (N=2) arXiv:1206.3478 (bosonic N=2) arXiv:1112.0069 (N=1)

09.06.2005 (Thursday)

Noncentral extension of AdS superalgebra

Regular Seminar Jeong-Hyuck Park (IHES-Paris)

16:00 IC
room H503

Four dimensional N=4 super Yang-Mills theory contains a bigger superalgebra than AdS or superconformal algebra, su(2,2/4). It corresponds to a noncentral extension of the latter. The talk is for both physicsts and mathematicans interested in a novel way of obtaining noncentral extensions of Lie algebras.