Finite-temperature Field Theory - Theoretical Physics (TIFR)
Finite-temperature Field Theory - Theoretical Physics (TIFR)
Finite-temperature Field Theory - Theoretical Physics (TIFR)
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Basics of Statistical <strong>Physics</strong> and Thermodynamics<br />
Scalar fields at finite <strong>temperature</strong><br />
Interacting scalar fields<br />
Statistical QM<br />
Simple examples<br />
One degree of freedom<br />
◮ Consider one state system with E = ω, and ignore zero<br />
point energy<br />
Ĥ | n〉 = ω ˆN | n〉 = n ω | n〉<br />
◮ For bosons/fermions with chemical potential µ, obtain<br />
∞∑<br />
Z b = Tr e −β(ω−µ) ˆN = 〈n | e −β(ω−µ) ˆN 1<br />
| n〉 =<br />
1 − e ,<br />
−β(ω−µ)<br />
Z f = Tr e −β(ω−µ) ˆN =<br />
n=1<br />
1∑<br />
〈n | e −β(ω−µ) ˆN | n〉 = 1 + e −β(ω−µ)<br />
n=1<br />
◮ Taking derivatives...<br />
N b =<br />
1<br />
e β(ω−µ) − 1 , E b = ωN b<br />
N f =<br />
1<br />
e β(ω−µ) + 1 , E f = ωN f<br />
logo<br />
Aleksi Vuorinen, CERN<br />
<strong>Finite</strong>-<strong>temperature</strong> <strong>Field</strong> <strong>Theory</strong>