New perspective on the Unruh effect

In this work, based on the worldline path integral representation of the vacuum energy in spacetime with a Lorentzian metric, we provide a new but complementary interpretation of the Unruh effect. We perform the quantization of the massless free scalar field in Rindler space, specifying initial and final conditions. After quantization, the final outcome for the vacuum energy is interpreted as world line path integrals. In this picture, we find that the Unruh radiation is made of real particles as well as real antiparticles. The prediction regarding the presence of antiparticles in the radiation might open new lines for the experimental detection of the effect. We present a thought experiment which offers a clear picture and supports the new interpretation.

Figure 1

Pictorial representation of the infinitely many loops in spacetime contributing to the vacuum energy. No particular coordinate system is needed to describe them.

Figure 2

Pictorial representation of the infinitely many loops in spacetime relevant to the vacuum energy calculation for an inertial observer. The blue lines are initial and final times in the Minkowski slicing. The arrows are representing the flow of time in the loop.

Figure 3

Pictorial representation of the infinitely many loops in spacetime as in Fig. 2, now in the context of the vacuum energy calculation for the Rindler observer.

Figure 4

Pictorial representation of the infinitely many loops in spacetime. The Rindler observer perspective of the vacuum processes contributing to the vacuum energy. The arrows are representing the flow of time in the paths.