DIAMOND / NV LAB
Control a qubit in diamond
Vary the duration of a microwave pulse and observe the calculated qubit state. Add noise and compare the simulated measurement outcomes.
The qubit is not the whole stone. We model two spin states at a special site in the crystal.
Top: certain 0. Bottom: certain 1. Sideways: either measurement result is possible. The sideways direction shows the phase.
A mathematical diagram, not an orbiting particle. Noise can shorten the vector. For Ramsey we show the state after the second pulse.
YOUR EXPERIMENT
How long is the right pulse?
A suitable pulse flips the qubit from 0 to 1. A pulse twice as long brings it back. Try 0.5 and 1 µs.
0 means the drive matches the transition exactly.
Noise makes the clear rhythm fade. These times are educational examples, not manufacturer data.
Slow motion for explanation. Animation duration is not computation time.
THE RESULT
Don’t guess. Calculate.
The curve shows the probability of reading 1. It is calculated from your settings.
Violet: your model · dashed: without noise
A single measurement yields 0 or 1. Many repetitions reveal this proportion.
No sample drawn yet.
Simulated ideal state measurements, not photon counts. Each repetition prepares the same state anew.
Why does this matter?
These experiments investigate how precisely a qubit can be controlled and how long it preserves its phase. This matters for quantum computers and sensitive quantum sensors. Here you can explore these relationships safely.
Model, limitations & sources
An effective two-level model of an isolated NV transition. Calculated in the rotating frame with the rotating-wave approximation and Markovian decay. Initialization is ideal; Ramsey also uses ideal, instantaneous, same-phase π/2 pulses. This is why that curve starts at 100%.
Drive: 1 MHz. With noise: T1 = 100 µs, Tφ = 2 µs; 1/T2 = 1/(2T1) + 1/Tφ. Without noise the relaxation times are infinite. No hyperfine structure, additional spin levels, optical dynamics or coupled qubits. Not a calibrated digital twin of a manufacturer device.
The calculation runs on your device, not our i9 or quantum hardware. Numerical model verification does not replace experimental validation.
- Sewani et al.: Coherent control of NV− centers in diamond in a quantum teaching lab
- NIST: Diamond NV Center Magnetometry
nv-effective-two-level-rwa-v1