Robust calibration of an optical-lattice depth based on a phase shift

Double-well systems loaded with one, two, or many quantum particles give rise to intriguing dynamics, ranging from Josephson oscillation to self-trapping. This work presents theoretical and experimental results for two distinct double-well systems, both created using dilute rubidium Bose-Einstein condensates with particular emphasis placed on the role of interaction in the systems. The first is realized by creating an effective two-level system through Raman coupling of hyperfine states. The second is an effective two-level system in momentum space generated through the coupling by an optical lattice. Even though the non-interacting systems can, for a wide parameter range, be described by the same model Hamiltonian, the dynamics for these two realizations differ in the presence of interactions. The difference is attributed to scattering diagrams that contribute in the lattice coupled system but vanish in the Raman coupled system. The internal dynamics of the Bose-Einstein condensates for both coupling scenarios is probed through a Ramsey-type interference pulse sequence, which constitutes a key building block of atom interferometers. These results have important implications in a variety of contexts including lattice calibration experiments and momentum space lattices used for quantum analog simulations.

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“…The agreement with the numerical solutions to Eqs. ( 35)- (36) [see the solid lines in Fig. 5(a)] is excellent.…”

Section: E Ramsey-type Pulse Sequence: Analytical Treatmentmentioning

confidence: 99%

Rabi oscillations and Ramsey-type pulses in ultracold bosons: Role of interactions

et al. 2020

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“…The harmonic potential of the hybrid trap U hyb (x) has an angular frequency ω x = 2π × 50 Hz. The dimensionless depth of the lattice s is independently and precisely calibrated [54] for each experiment presented here.…”

Section: A Bec Experimental Setupmentioning

confidence: 99%

Quantum State Control of a Bose-Einstein Condensate in an Optical Lattice

et al. 2021

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We report on the efficient design of quantum optimal control protocols to manipulate the motional states of an atomic Bose-Einstein condensate (BEC) in a one-dimensional optical lattice. Our protocols operate on the momentum comb associated with the lattice. In contrast to previous works also dealing with control in discrete and large Hilbert spaces, our control schemes allow us to reach a wide variety of targets by varying a single parameter, the lattice position. With this technique, we experimentally demonstrate a precise, robust and versatile control: we optimize the transfer of the BEC to a single or multiple quantized momentum states with full control on the relative phase between the different momentum components. This also allows us to prepare the BEC in a given eigenstate of the lattice band structure, or superposition thereof.

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“…Precision measurement of optical lattice [1] depths is important for a broad range of fields in atomic and molecular physics [2,3], most notably in atom interferometry [4,5], many body quantum physics [6,7], accurate determination of transition matrix elements [8][9][10][11][12], and, by extension, ultraprecise atomic clocks [13,14]. Lattice depth measurement schemes include methods based on parametric heating [15], Rabi oscillations [16], and sudden lattice phase shifts [17]. The most commonly used scheme is Kapitza-Dirac scattering [18], where an ultracold atomic gas is exposed to a pulsed laser standing wave and theoretical predictions for the fraction of atoms found in each of the allowed momentum states are fitted to time of flight measurements [7,[19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Lattice-depth measurement using multipulse atom diffraction in and beyond the weakly diffracting limit

2019

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Precise knowledge of optical lattice depths is important for a number of areas of atomic physics, most notably in quantum simulation, atom interferometry and for the accurate determination of transition matrix elements.In such experiments, lattice depths are often measured by exposing an ultracold atomic gas to a series of offresonant laser-standing-wave pulses, and fitting theoretical predictions for the fraction of atoms found in each of the allowed momentum states by time of flight measurement, after some number of pulses. We present a full analytic model for the time evolution of the atomic populations of the lowest momentum-states, which is sufficient for a "weak" lattice, as well as numerical simulations incorporating higher momentum states for both relatively strong and weak lattices. Finally, we consider the situation where the initial gas is explicitly assumed to be at a finite temperature. * b.t.beswick@durham.ac.uk † i.g.hughes@durham.ac.uk ‡ s.a.gardiner@durham.ac.uk 1 In practice, this additive effect is only maintained for a certain number of pulses set by the lattice depth, as we discuss in section IV. 2 The quantum degeneracy is not important in our analysis, as the requirement is simply for a very narrow initial momentum spread. 3 It is conventional to define the lattice depth with respect to a potential of the form U 0 sin 2 (K x/2). In this work we refer to the lattice depth as V = −U 0 /2 = − Ω 2 /8∆ for a laser Rabi frequency Ω and detuning ∆ ≡ ω L −ω 0 .

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Robust calibration of an optical-lattice depth based on a phase shift

Cited by 16 publications

References 38 publications

Rabi oscillations and Ramsey-type pulses in ultracold bosons: Role of interactions

Rabi oscillations and Ramsey-type pulses in ultracold bosons: Role of interactions

Quantum State Control of a Bose-Einstein Condensate in an Optical Lattice

Lattice-depth measurement using multipulse atom diffraction in and beyond the weakly diffracting limit

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