  In this work, we show that quantum state discrimination can be modified due
to a change in the underlying topology of a system. In particular, we
explicitly demonstrate that the quantum state discrimination of systems with
underlying discrete topology differs from that of systems with underlying
continuous topology. Such changes in the topology of a spacetime can occur in
certain quantum gravity approaches. In fact, all approaches to quantum gravity
can be classified into two types: those with underlying continuous topology
(such as string theory) and those with an underlying discrete topology (such as
loop quantum gravity). We demonstrate that the topology of these two types of
quantum gravity approaches has different effects on the quantum state
discrimination of low-energy quantum systems. We also show that any
modification of quantum mechanics, which does not change the underlying
topology, does not modify quantum state discrimination.
