  In this study, we investigate the signature of the Unruh effect in quantum
radiation from an accelerated charged particle interacting with vacuum
fluctuations. Because a charged particle in uniformly accelerated motion
exhibits thermal random motion around the classical trajectory because of the
Unruh effect, its quantum radiation might be termed Unruh radiation. We show
that the energy flux of the quantum radiation is negative and that its
amplitude is smaller than the classical Larmor radiation by a factor of $a/m$,
where $a$ is the acceleration and $m$ is the mass of the particle. The total
radiation flux of the classical Larmor radiation and the quantum radiation is
positive; therefore, the quantum radiation appears to suppress the total
radiation. Interestingly, the results are consistent with the prediction for
the quantum correction to classical Larmor radiation, which were obtained using
a different approach.
