Breakthrough Prize in Fundamental Physics 2023
เสวนาสาธารณะ 6 ตุลาคม 2565
Photo credit: Breakthrough Prize
Dancing with Qubits
How they can change the world
Qubit
Probabilistic prediction
Choice of measurement +
Quantum state =
Certainty
Fully random
Somewhat random
Qubit
Even ideal measurements cause "collapse of the wave function"
or
or
or
But in quantum theory, different choices of measurement can be incompatible
Not too different from updating your belief
Entanglement
These different choices of measurement can reveal stronger-than-classical correlation when the qubits are entangled
If not for these measurement choices, entanglement would be no different from a classical correlation
\(\to\) See Nobel Prize in Physics 2022
BB84 Quantum Key Distribution
Modified from Zbinden et al. Appl. Phys. B (1998)
Stephen Wiesner (1942-2021) proposed using qubits to create money that would be impossible to counterfeit by the no-cloning theorem, while the authenticity of the money could be verified by measuring the qubits in the correct basis.
Wiesner's Quantum Money
(This is before the "official" discovery of no-cloning theorem and super-dense coding!)
Early Timeline of Quantum Computing
1981
Quantum computing for simulation of physics
1985
Quantum Turing machine, Deutsch-Josza algorithm (1992)
1994
Shor's factoring algorithm, quantum error correcting codes (1995)
1994
Implementation proposal using trapped ions
