Level 3

Phase

Phase is hidden direction inside an amplitude that changes how paths combine later.

Try it now

Visualize

Phase may not show up immediately in counts, but it can change later interference.

Understand

S and T gates adjust phase without acting like ordinary flips.

Why it matters

Phase is central to QFT, Shor-style period finding, and interference tricks.

Misconception

If counts do not change immediately, the circuit state may still have changed.

Apply

Place phase gates between two H gates and observe the final probability shift.

Example DSL

# Phase kick with S and T
qubits 1
H 0
S 0
T 0
H 0
MEASURE 0
Run in Simulator

Quick check

Why can phase be hard to notice?