61 citations · 389 across the 27 of their papers we have counts for
4 papers · 1 filter
Temperature-Enhanced Critical Quantum Metrology
Laurin Ostermann, Karol Gietka
We show that the performance of critical quantum metrology protocols, counter-intuitively, can be enhanced by finite temperature. We consider a toy-model squeezing Hamiltonian, the…
Combining critical and quantum metrology
Christoph Hotter, Helmut Ritsch, Karol Gietka
Critical metrology relies on the precise preparation of a system in its ground state near a quantum phase transition point where quantum correlations get very strong. Typically thi…
Unique Steady-State Squeezing in a Driven Quantum Rabi Model
Karol Gietka, Christoph Hotter, Helmut Ritsch
Squeezing is essential to many quantum technologies and our understanding of quantum physics. Here we develop a theory of steady-state squeezing that can be generated in the closed…
Squeezing of the quantum electromagnetic vacuum
Karol Gietka
It is commonly agreed that the electromagnetic vacuum is not empty but filled with virtual photons. This leads to effects like Lamb shift and spontaneous emission. Here we argue th…