# Arrow of time and quantum physics

May 19, 2023

Based on the hypothesis that the (non-reversible) arrow of time is intrinsic
in any system, no matter how small, the consequences are discussed. Within the
framework of local quantum physics it is shown how such a semi-group action of
time can consistently be extended to that of the group of spacetime
translations in Minkowski space. In presence of massless excitations, however,
there arise ambiguities in the theoretical extensions of the time translations
to the past. The corresponding loss of quantum information on states upon time
is determined. Finally, it is explained how the description of operations in
classical terms combined with constraints imposed by the arrow of time leads to
a quantum theoretical framework. These results suggest that the arrow of time
is fundamental in nature and not merely a consequence of statistical effects on
which the Second Law is based.

Keywords:

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