On noise-resolution uncertainty in quantum field theory

Dissipation, noise, and vacuum decay in quantum field theory.

We study the process of vacuum decay in quantum field theory focusing on the stochastic aspects of the interaction between long- and short-wavelength modes. This interaction results in a diffusive behavior of the reduced Wigner function describing the state of long-wavelength modes, and thereby to a finite activation rate even at zero temperature. This effect can make a substantial contribution...

Lectures on quantum field theory

Notes on Quantum Field Theory

UCSB Notes for the first quarter of a QFT course, based mostly on ϕ 3 theory in six dimensions. Please send any comments or corrections to

On Thermal Entropy in Quantum Field Theory

Standard entropy calculations in quantum field theory, when applied to a subsystem of definite volume, exhibit area-dependent UV divergences that make a thermodynamic interpretation troublesome. Such divergences cannot be reabsorbed by local counterterms although, with a rather unusual procedure, they can be subtracted from the final result. A key issue here is which set of quantum degrees of f...

On momentum operator in quantum field theory

The interrelations between the two definitions of momentum operator, via the canonical energy-momentum tensorial operator and as translation operator (on the operator space), are studied in quantum field theory. These definitions give rise to similar but, generally, different momentum operators, each of them having its own place in the theory. Some speculations on the relations between quantum ...