Table 1 Precision bounds of the most relevant models in quantum-enhanced metrology.
From: The elusive Heisenberg limit in quantum-enhanced metrology
Channel considered | Classical simulation | Channel extension |
|---|---|---|
Depolarisation |
|
|
Dephasing |
|
|
Spontaneous emission | NA |
|
Lossy interferometer | NA |
|
- NA, not available.
- The bounds are derived using the two methods discussed in the paper. All the bounds are of the form
, where constant factors are given in the table. Classical simulation method does not provide bounds for spontaneous emission and lossy interferometer, as these channels are ϕ-extremal. For the dephasing model, it surprisingly yields an equally tight bound as the more powerful channel extension method.
, where constant factors are given in the table. Classical simulation method does not provide bounds for spontaneous emission and lossy interferometer, as these channels are ϕ-extremal. For the dephasing model, it surprisingly yields an equally tight bound as the more powerful channel extension method.