Skip to main content
← zooRabi Chevronclick + drag on heatmap

Rabi Frequency: Ω = 4.0 MHz

T₂ Dephasing: Off

Max Pulse: 2.0 μs

Freq Span: ±40 MHz

Selected Point

Drive freq8.5000 GHz
Detuning Δ0.0 MHz
Pulse length0.500 μs
Ωeff4.00 MHz
P(|1⟩)0.7081

Accuracy & Method

P(|1⟩) = (Ω/Ω_eff)² sin²(Ω_eff·t/2)
Numerical error: None (closed-form, no integration)
Approximation
Rotating wave approximation (RWA). Valid when Ω « fqubit — always true for superconducting qubits (MHz drive vs GHz qubit). Counter-rotating terms are dropped.
What you'd measure
Measure qubit in Z basis, count |1⟩ outcomes. This is the standard readout — no extra gates needed.
Damping model
Simplified: all components decay as exp(−t/T₂). Real qubits have separate T₁ (population relaxation, σz → equilibrium) and T₂ (dephasing, σx,y → 0). Typically T₂ ≤ 2T₁.
Lab context
Chevron scans are a standard calibration step for superconducting qubits. You sweep drive frequency and pulse length to find the π-pulse time (first P(|1⟩)=1 at resonance). The V-opening directly encodes Ω.

Recipes

Rabi Chevron

The characteristic “V” pattern from sweeping drive frequency vs pulse length on a superconducting qubit.

At resonance: full-amplitude oscillations at Ω. Off-resonance: faster oscillations but reduced amplitude.

P(|1⟩) = (Ω/Ωeff)² sin²(Ωefft/2)

Related
Resonance →Bloch Sphere →Noise Channels →All Tools →

About Rabi Oscillations

Rabi oscillations are the coherent oscillation of a qubit between |0⟩ and |1⟩ under a resonant driving field. They are the physical basis of single-qubit gates: a π-pulse (half a Rabi cycle) flips the qubit, and a π/2-pulse creates a superposition.

When the drive frequency is detuned from the qubit's resonance, the oscillations speed up but no longer reach full inversion — this is called the generalized Rabi frequency Ω' = √(Ω² + Δ²). Real qubits also experience decoherence: T₁ relaxation causes energy decay toward |0⟩, while T₂ dephasing causes the oscillation envelope to decay.

This simulator lets you tune the driving strength, detuning, and dephasing time to see how these parameters shape the qubit dynamics on the Bloch sphere and in the measurement probability.