Where the idea came from
Einstein and Rosen described a bridge-like construction in general relativity in 1935. Modern wormhole physics grew from asking whether spacetime could contain connections between distant regions without requiring an ordinary journey through the space between them.
Why traversability is difficult
The classic Einstein–Rosen bridge is not a practical tunnel that a traveller can simply cross. Traversable models generally require unusual stress-energy conditions, often described as negative energy or violations of classical energy conditions, to keep the throat open.
What quantum physics changes
Quantum fields can produce limited negative-energy effects in special circumstances, but that does not demonstrate a macroscopic, stable wormhole. Proposals linking wormholes, quantum entanglement or holography are active theoretical research, not observations of tunnels in spacetime.
What evidence would count
A serious detection would need an astronomical signature that is hard to reproduce with black holes, lensing, plasma or ordinary compact objects, together with a model that predicts the same observations. No such confirmed signature exists.
Research record
Morris, Thorne & Yurtsever (1988), Physical Review LettersPeer-reviewed · open sourceCaltechAUTHORS record for Morris, Thorne & YurtseverInstitutional archive · open sourceCould Wormholes Ever Be Real?
Direct answer: Wormholes are allowed in important families of gravitational theory, but no traversable wormhole has been observed and no known engineering method can build or stabilise one.
Physically conceivable in theory; empirically unconfirmed. The gap between a valid spacetime geometry and a usable shortcut remains enormous.