Quantum Computing

Basic Concepts and Applications

What is Quantum Computing? Conventional computers use bits

Quantum computers use “qubits”

– Can be both 0 and 1 at once

– When measured, “snaps” into either 0 or 1

– Coefficient marks the probability of which state the qubit will “snap” into

Quantum Interference:An Experiment

Quantum Interference:An Experiment

Implications of Superposition

Each register holds all possible values

Implications of Superposition

Computation is massively parallel 4-qubit register holds all 24 values Running a function on the register is like

that function running on all possible values within the register– This would take 24 times longer on a

conventional computer

Problems

Decoherence– Computation spreads across close matter

– Superpositions spread, thus degrading the computation

Hardware– Purdue scientists created

“quantum transistor”

Applications

Massively parallel computation allows– Breaking of RSA– Solving previously NP-complete problems

Quantum encryption– Light beam cannot be intercepted without

destroying the message (Heisenberg Uncertainty Principle)

Quantum Teleportation

Quantum Teleportation

Subatomic particles “intertwined”

When one “flips,” its partner does too

Allows instantaneous communication that appears to be incapable of interception

Conclusions

Quantum Computing is massively powerful– Massively parallel computation

Can break RSA Opens up doors to new forms of encryption Allows a new type of information

transmission