  We introduce probability thermodynamics and probability quantum fields. By
probability we mean that there is an unknown operator, physical or nonphysical,
whose eigenvalues obey a certain statistical distribution. Eigenvalue spectra
define spectral functions. Various thermodynamic quantities in thermodynamics
and effective actions in quantum field theory are all spectral functions. In
the scheme, eigenvalues obey a probability distribution, so a probability
distribution determines a family of spectral functions in thermodynamics and
quantum field theory. This leads to probability thermodynamics and probability
quantum fields determined by a probability distribution. In constructing
spectral functions, we encounter a problem. The conventional definition of
spectral functions applies only to lower bounded spectra. In our scheme,
however, there are two types of spectra: lower bounded spectra, corresponding
to the probability distribution with nonnegative random variables, and the
lower unbounded spectra, corresponding to probability distributions with
negative random variables. To take the lower unbounded spectra into account, we
generalize the definition of spectral functions by analytical continuation. In
some cases, we encounter divergences. We remove the divergence by a
renormalization procedure. Moreover, in virtue of spectral theory in physics,
we generalize some concepts in probability theory. For example, the
moment-generating function in probability theory does not always exist. We
redefine the moment-generating function as the generalized heat kernel
introduced in this paper, which makes the concept definable when the definition
in probability theory fails. Thermodynamic quantities, vacuum amplitudes,
one-loop effective actions, and vacuum energies for various probability
distributions are presented.
