Many-body quantum metrology with scalar bosons in a single potential well

Abstract

We theoretically investigate the possibility of performing high precision estimation of an externally imposed acceleration using scalar bosons in a single-well trap. We work at the level of a two-mode truncation, valid for weak to intermediate two-body interaction couplings. The splitting process into two modes is in our model entirely caused by the interaction between the constituent bosons and is hence neither due to an externally imposed double-well potential nor due to populating a spinor degree of freedom. The precision enhancement gained by using various initial quantum states using a two-mode bosonic system is well established. Here we therefore instead focus on the effect of the intrinsic dynamics on the precision, where, in a single well, the Hamiltonian assumes a form different from that of the typical double-well case. We demonstrate how interactions can significantly increase the quantum Fisher information maximized over initial states as well as the quantum Fisher information for a fragmented or a coherent state, the two many-body states that can commonly represent the ground state of our system.

Adiabatic preparation of entangled, magnetically ordered states with cold bosons in optical lattices

“…At the same time there has been a lot of interest in questions of where atoms in optical lattices can produce quantum states with substantial entanglement in a form that could be useful for quantum enhanced metrology. In particular, several recent works have discussed the availability of such states near certain phase transition boundaries [17][18][19][20][21][22][23][24][25][26][27]. The usefulness of this entanglement for metrology is generally quantified via the QFI [28][29][30][31][32][33], which makes it possible to characterize the potential of parameter estimation with a particular initial state to beat the standard quantum limit (SQL) or shot noise limit of a scaling as 1/ √ M, where M is the number of particles in the system.…”

Adiabatic preparation of entangled, magnetically ordered states with cold bosons in optical lattices

“…At the same time there has been a lot of interest in questions of where atoms in optical lattices can produce quantum states with substantial entanglement in a form that could be useful for quantum enhanced metrology. In particular, several recent works have discussed the availabilty of such states near certain phase transition boundaries [12][13][14][15][16][17][18][19]. The usefulness of this entanglement for metrology is generally quantified via the Quantum Fisher Information (QFI) [20][21][22][23], which makes it possible to characterize the potential of parameter estimation with a particular initial state to beat the Standard Quantum Limit (SQL) or shot noise limit of a scaling as 1/ √ M , where M is the number of particles in the system.…”