Suppose someone drops a clock and it tunnels through the Earth. What time will have elapsed according to the clock when it emerges on the other side of the Earth?
Is it only tunneling in space or can it also tunnel in time?
#3
genneth
979
2
Time is one of those annoying issues in quantum mechanics. In non-relativistic QM, time isn't even a state of the system -- there is no operator that corresponds to measuring it. In relativistic QM, you've got a multiplicity of time and proper times are difficult to acertain without resorting to rather advanced applications of statistical mechanics and QM together. The basic idea is that time flow is always determined, in some sense, by the statistical state, and not just by the background structures or even just the dynamics.
Rather hazily, I might try to understand the situation via the Feynman paths method -- the initial state is propagated in spacetime via all possible routes, and the result of a measurement will have a probability distribution given by the interference possible. Assuming that the clock is a fundamental particle (it doesn't explode as it interacts with the Eath), and measures its proper time, the answer would be some inference pattern, in time.
#4
GleefulNihilism
35
0
As I understand it, and I claim no more authority then an interested amatuer, if the clock does true quamtum tunneling then it will reappear on the other side of the Earth instantly.
Insights auto threads is broken atm, so I'm manually creating these for new Insight articles.
Towards the end of the first lecture for the Qiskit Global Summer School 2025, Foundations of Quantum Mechanics, Olivia Lanes (Global Lead, Content and Education IBM) stated...
Source: https://www.physicsforums.com/insights/quantum-entanglement-is-a-kinematic-fact-not-a-dynamical-effect/
by @RUTA
If we release an electron around a positively charged sphere, the initial state of electron is a linear combination of Hydrogen-like states. According to quantum mechanics, evolution of time would not change this initial state because the potential is time independent. However, classically we expect the electron to collide with the sphere. So, it seems that the quantum and classics predict different behaviours!
I don't know why the electrons in atoms are considered in the orbitals while they could be in sates which are superpositions of these orbitals? If electrons are in the superposition of these orbitals their energy expectation value is also constant, and the atom seems to be stable!