Limitations of the dissipative quantum Fisher information in Liouville space
Tatiana Iakovleva, Ruvi Lecamwasam, Jason Twamley · 2026
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Description
Tatiana Iakovleva and two colleagues stress-test a shortcut for measuring how much information a quantum system holds about a quantity worth estimating. Quantum Fisher information sets the ultimate precision limit for quantum sensors, but real systems leak into their surroundings, which makes it hard to compute. A reformulation in Liouville space, where states become vectors, promised an easier dissipative version. Their 2026 paper derives exact relations between the two quantities for a qubit, for qudit systems, and for a harmonic oscillator.
For a qubit, the true value can be recovered from the dissipative one by a mapping that depends on purity. In higher dimensions the conversion tangles beyond any compact form. The dissipative quantity sometimes sits above and sometimes below the true one, so it bounds nothing reliably. The authors conclude its numbers cannot be read at face value, and map where the Liouville approach helps or misleads.
Catalog record
| CREATOR | Tatiana Iakovleva, Ruvi Lecamwasam, Jason Twamley |
|---|---|
| YEAR | 2026 |
| COLLECTION | PAPERS |
| FORMAT | TXT |
| FILE SIZE | 27206 |
| LICENSE | https://creativecommons.org/licenses/by/4.0 |
| RIGHTS | CC BY |
| SOURCE | Europe PMC |