Emergent spacetime

When you look into the mirror, you see yourself as a localized, organic object. You don't see your wavefunction! The question of how the classical world emerge from the underlying quantum world is a very interesting and profound question. The leading paradigm to describe such process is called "decoherence". Decoherence realizes that the measurement process is quantum in nature, because both the system being measured and the measurement device are ultimately quantum. Upon measurement, the "ready state" of the apparatus becomes entangled with the quantum system itself and the information about the system is recorded in the newly entangled state. Decoherence, by itself, does not fully resolve the measurement problem and is still far from explaining how classical physics emerge from quantum physics. Nevertheless, it is the most promising program to pursue.

It is creepy to ask: what if spacetime itself is quantum in nature? If the localized, well-shaped classical stuff are ultimately quantum, could the spacetime background containing them be also ultimately quantum? In such case, the spacetime that we perceive is called "emergent spacetime". The idea of emergent space has been put forward using the concept of quantum entanglement. "More entanglement" between nearby quanta would imply "closer space". The emergent time program is less well-understood as time is even more special than space in that it only has one direction.

I'm interested in exploring the fundamental quantum nature of space and time, and how the classical world emerge from the quantum world.

• Ngo Phuc Duc Loc, "Insights of quantum time into quantum evolution", arXiv:2306.11675

• Ngo Phuc Duc Loc, "Time-system entanglement and special relativity", Mod. Phys. Lett. A 39, 2350183 (2024)