A friend argues: "A particle in a state with energy spread can borrow an extra of…
PHYSICS · Subjective · Fermi University Physics · Quantum Mechanics · The formalism of quantum mechanics · The formalism of quantum mechanics
Quantum Mechanics: From the Photon to the Hydrogen Atom, Ch Observables, commutators and the uncertainty relations
Problem
A friend argues: "A particle in a state with energy spread ΔE=0.40eV can borrow an extra 0.40eV of energy for a time Δt=ℏ/ΔE, long enough to tunnel through a barrier it could not otherwise cross, before paying the energy back." Explain what is wrong with this argument, evaluate the friend's Δt=ℏ/ΔE, and say what ΔE and Δt actually mean for this state.