Memory, spin echo and noise spectroscopy
Research context
research method · conditional · As of 2026-10-10
For stationary zero-mean Gaussian phase noise f(t), a qubit coherence factor is exp[−½∫₀ᵀ∫₀ᵀK(t−t′)dt dt′], where K is the covariance of angular-frequency noise.
Key knowledge
For stationary zero-mean Gaussian phase noise f(t), a qubit coherence factor is exp[−½∫₀ᵀ∫₀ᵀK(t−t′)dt dt′], where K is the covariance of angular-frequency noise. Echo control changes the temporal weighting. Coloured noise can produce nonexponential decay; a fitted damping rate alone does not demonstrate Markovianity.
Values and equations
W(T)=exp[−½∫₀ᵀdt∫₀ᵀdt′K(t−t′)]
- W
- Dimensionless coherence factor
- T,t,t′
- Times s
- f
- Angular-frequency noise s⁻¹
- K
- Noise covariance s⁻²
Conditions and scope
- Commuting pure-dephasing Hamiltonian ħf(t)σ_z/2, specified preparation, Gaussian stationary noise and calibrated pulses.
- Non-Gaussian noise or transverse relaxation needs a different model; the experiment samples a filter-weighted spectrum rather than every frequency independently.
Sources · 1
References
Sources retain their recorded scope. A source link alone does not establish verification of every statement.
Evidence and review
Inspected §§3.1.2, 3.2.1, 3.2.4, 3.2.6, 3.5 and 3.6: probabilities, operations, complete positivity, semigroups and coloured noise; source check dated 2026-10-10. Scope is limited to the cited statements, equations and assumptions, not the whole publication.
2026-10-10 · Author source inspection of the displayed claim, model assumptions and equations; independent exact-content and branch-inventory review is a separate gate. Contemporary status is a dated snapshot, not a promise of ongoing monitoring.
Entry details
Permanent link to this entry ↗- Record identity
- research-physics-coloured-quantum-noise
- Revision
- research.1
- Structured reference record
- Postgraduate & research reference