Gordon Godfrey Theoretical Seminars 2006
Violation
of the fundamental parity and time reversal symmetries: manifestations
in solid state physics.
Timur
Mukhamedjanov
Date
12 pm, Tuesday, 14 February, 2006
School of Physics,
Room 5
Abstract:
Measurements of atomic parity violation provide important cross-tests
of the standard model of electroweak interactions by probing these interactions
in the domain of low energies. The effects of parity nonconservation
in atoms, both dependent and not dependent on nuclear spin, have been
successfully measured in experiments. The existence of permanent electric
dipole moment (EDM) of a quantum particle requires that the fundamental
parity (P) and time-reversal (T) symmetries are violated. By the CPT
theorem, this would also mean the violation of combined CP (charge conjugation-parity)
symmetry. Studies of T and CP violation in nature provide valuable information
for theories of baryogenesis, and for understanding of fundamental interactions
in general.
Recently,
a new wave of experiments has been initiated to measure the effects
of P and T violation in solid state materials. The possibility to substantially
increase the experimental sensitivity lies in the larger number of particles
compared to the atomic experiments and in the specific collective effects
in solids. The downside is the typically larger level of systematics.
The following effects due to violation of T and P at fundamental level
in solids will be discussed:
- effects due to the electron EDM in gadolinium garnets, where increase
of experimental sensitivity to the electron EDM of several orders of
magnitude is possible;
- effects due to the nuclear Schiff moment of 207Pb in ferroelectric
lead-titanate; this possibility looks particularly promising, offering
a potential 10 orders of magnitude increase of sensitivity to the nuclear
Schiff moment, which puts the standard model prediction for this value
within experimental reach.
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