Abstract
Quantum interference lies at the heart of quantum mechanics. By utilizing destructive interference, it is possible to transfer a physical object between two states without populating an intermediate state which is necessary to connect the initial and final states. A famous application is a technique of stimulated Raman adiabatic passage, where atomic internal states can be transfered with high efficiency regardless of lossy intermediate states. One interesting situation is a case where the initial and final states are spatially well separated. Quantum mechanics allows a particle to move without practical possibility of being found at the intermediate area. Here we demonstrate this spatial adiabatic passage with ultracold atoms in an optical lattice. Key to this is the existence of dark eigenstates forming a flat energy band, with effective transfer between two sublattices being observed. This work sheds light on a study of coherent control of trapped cold atoms.
Highlights
Quantum interference lies at the heart of quantum mechanics
By applying two laser pulses in so-called counterintuitive order so that θ changes from 0 to π/2, the dark states smoothly evolve from ∣B〉 into ∣C〉. This process is well-known as stimulated Raman adiabatic passage (STIRAP)4–6, and has been an important technique for robust population transfer between two atomic/molecular states
Such processes, named spatial adiabatic passage (SAP), offer paradoxical transport without transit7,8 where matter waves are transported without populating the intermediate spatial region
Summary
Quantum interference lies at the heart of quantum mechanics. By utilizing destructive interference, it is possible to transfer a physical object between two states without populating an intermediate state which is necessary to connect the initial and final states. Quantum mechanics allows a particle to move without practical possibility of being found at the intermediate area We demonstrate this spatial adiabatic passage with ultracold atoms in an optical lattice. By applying two laser pulses in so-called counterintuitive order so that θ changes from 0 to π/2, the dark states smoothly evolve from ∣B〉 into ∣C〉 This process is well-known as stimulated Raman adiabatic passage (STIRAP), and has been an important technique for robust population transfer between two atomic/molecular states. Natural interests arise for a special case that the states of interest represent a matter wave of a quantum particle and the initial and the final states are spatially well isolated Such processes, named spatial adiabatic passage (SAP), offer paradoxical transport without transit where matter waves are transported without populating the intermediate spatial region. It is interesting to consider the case of interacting many-body systems such as Bose–Einstein condensates
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