Abstract
In contrast to the fully projective limit of strong quantum measurement, where the evolution is locked to a small subspace (quantum Zeno dynamics), or even frozen completely (quantum Zeno effect), the weak non-projective measurement can effectively compete with standard unitary dynamics leading to nontrivial effects. Here we consider global weak measurement addressing collective variables, thus preserving quantum superpositions due to the lack of which path information. While for certainty we focus on ultracold atoms, the idea can be generalized to other multimode quantum systems, including various quantum emitters, optomechanical arrays, and purely photonic systems with multiple-path interferometers (photonic circuits). We show that light scattering from ultracold bosons in optical lattices can be used for defining macroscopically occupied spatial modes that exhibit long-range coherent dynamics. Even if the measurement strength remains constant, the quantum measurement backaction acts on the atomic ensemble quasi-periodically and induces collective oscillatory dynamics of all the atoms. We introduce an effective model for the evolution of the spatial modes and present an analytic solution showing that the quantum jumps drive the system away from its stable point. We confirm our finding describing the atomic observables in terms of stochastic differential equations.
Highlights
Quantum measurement is one of the most intriguing aspects of quantum mechanics
We have shown that light scattering from ultracold gases in optical lattice can be used for partitioning the system into macroscopically occupied spatial modes with non-trivial overlap which preserve long-range coherence
We formulated an effective model for the dynamics of this mode in a single quantum trajectory, mapping each spatial mode to a single ‘well’ and describing its properties in term of collective variables
Summary
Collective dynamics of multimode bosonic systems induced by weak quantum measurement Gabriel Mazzucchi, Wojciech Kozlowski, Santiago F Caballero-Benitez and Igor B Mekhov. Any further distribution of this work must maintain weak non-projective measurement can effectively compete with standard unitary dynamics leading to attribution to the nontrivial effects. We consider global weak measurement addressing collective variables, author(s) and the title of the work, journal citation preserving quantum superpositions due to the lack of which path information. Focus on ultracold atoms, the idea can be generalized to other multimode quantum systems, including various quantum emitters, optomechanical arrays, and purely photonic systems with multiple-path interferometers (photonic circuits). We introduce an effective model for the evolution of the spatial modes and present an analytic solution showing that the quantum jumps drive the system away from its stable point. We confirm our finding describing the atomic observables in terms of stochastic differential equations
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