Mar. 10, 2026 (In person)

Prof. Keh-Fei Liu

Location: Swiatecki Lounge B70 annex - 228

Time: 4:00pm Pacific Time

ZOOM for those who are unable to come in-person: LINK

Host: Yuuka Kanakubo

Title: Pressure-Energy Equations of State of Hadrons, Superconductor

Vortices, and the Cosmos

Abstract: The pressure–energy relations in the nucleon are derived from the

gravitational form factors, which parameterize matrix elements of the

energy-momentum tensor (EMT), together with EMT conservation. The static

pressure distribution arising from the Lorentz trace part of the EMT, as

manifested in the spatial stress $\frac{1}{3} T^{ii}$, equals minus the

corresponding trace part of the energy density, which can be understood

in terms of the gluon and quark condensates.  It can be shown that this

trace-anomaly- and sigma-term-induced pressure plays a fundamental role

in the confinement dynamics of QCD. In contrast, the dynamic pressure

distribution from the traceless part of the spatial stress tensor equals

$1/d$ of the corresponding traceless part of the energy density, where

$d$ is the spatial dimension. We point out that the same pressure–energy

relations also hold for vortices in type-II superconductors, where the

static pressure–energy relation originates from the Cooper-pair

condensate. Furthermore, identical equations of motion appear in the

$\Lambda{\rm CDM}$ model of cosmology, where the static pressure–energy

relation arises from the cosmological constant.

[postponed]

Prof. Jen-Chieh Peng  (University of Illinois at Urbana-Champaign)

Location: Swiatecki Lounge B70 annex - 228

Time: 4:00pm Pacific Time

ZOOM for those who are unable to come in-person: LINK

Host: Keh-Fei Liu

Title: Evolution of Helicity Property of Relic Neutrinos and Implications 

on Their Detection

Abstract: Neutrinos in the early Universe decoupled essentially in helicity eigenstates.

As they propagate through the Universe, their helicities could be modified via

two effects. First, neutrinos with a finite magnetic moment would rotate their

spins with respect to their momenta as they encounter cosmic magnetic fields,

modifying their helicities. Second, the bending of neutrino's spin by a

gravitational field lags the bending of its momentum, again modifying its helicity. 

We study both effects and investigate the implications of the

helicity modification on the detection of relic neutrinos using the Inverse

Tritium Beta Decay (ITBD) reaction. We find that the ITBD rate depends

sensitively on the neutrino mass hierarchy and on the Dirac or Majorana nature

of the neutrinos. This talk is based on several papers in collaboration with 

Gordon Baym.