No, quantum mechanics does not deny the existence of the past. Quantum mechanics is a fundamental theory that describes the behavior of particles and physical systems on the microscopic scale. It provides a mathematical framework for understanding the probabilistic nature of quantum phenomena.
In quantum mechanics, the evolution of a quantum system is described by a wave function, which encodes the probabilities of different outcomes. When a measurement is made on a quantum system, the wave function "collapses" into one of the possible outcomes, corresponding to a definite value being observed.
However, this probabilistic nature of quantum mechanics does not negate the existence of the past. In fact, quantum mechanics can accurately describe the behavior of systems across time, including the past. The theory allows for the prediction of future outcomes based on the past and present states of a system.
The notion of time, including the existence of the past, is a fundamental aspect of our everyday experience and is not in conflict with quantum mechanics. While quantum mechanics introduces some unique features compared to classical physics, it does not invalidate the concept of the past or the arrow of time.
It's worth noting that there are still open questions and ongoing research about the nature of time and its relationship with quantum mechanics. Some theoretical frameworks, such as quantum cosmology, explore the possibility of time being emergent from more fundamental quantum principles. However, these ideas are still speculative and subject to further investigation and debate.