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Katya Fouka

Publications and source records attributed to Katya Fouka.

3 recordsLinked to original sources

Engineering Zeeman-manifold quintets using state-dependent light shifts in neutral atoms

We present a general method for engineering qudits through individually addressable transitions between Zeeman sublevels, achieved by combining a large linear Zeeman shift with a state-dependent light shift. This approach lifts the degeneracy between adjacent states while simultaneously tuning their energy splittings into the radio-frequency (RF) domain, enabling coherent manipulation within the Zeeman manifold using experimentally accessible drive frequencies. As a concrete realization, we investigate the implementation of an $SU(5)$ quintet encoded in the Zeeman sublevels of the long-lived $^3\mathrm{P}_2$ state of neutral $\mathrm{^{88}Sr}$ atoms confined in far-detuned, $\sigma^{-}$-polarized optical tweezers. Using realistic experimental parameters, we numerically demonstrate full control of the quintet manifold, including initialization into a specific $SU(5)$ basis state via a multi-photon transfer, coherent state- and site-selective single-qudit rotations driven by RF fields, and fast state-selective optical readout. Our simulations predict state-preparation fidelities of $\mathcal{F} \simeq 0.99$ within less than $1~$us, single-qudit gate fidelities of $F$ $\simeq 0.99$ with $\pi$-pulse durations of $\sim1.4~$us, and fast destructive imaging with durations below $10~$us under ideal conditions. These results establish a broadly applicable framework for high-fidelity control of Zeeman sublevel-encoded qudits and highlight the $^3\mathrm{P}_2$ manifold in strontium as a promising platform for scalable qudit-based quantum technologies.

physics.atom-ph

Multilevel Electromagnetically Induced Transparency Cooling

Electromagnetically Induced Transparency (EIT) cooling is a well-established method for preparing trapped ion systems in their motional ground state. However, isolating a three-level system, as required for EIT cooling, is often challenging or impractical. Nonetheless, multilevel systems can inherently host dark states. In this work, we extend the EIT cooling framework to such multilevel systems. We develop a formalism to accurately determine the cooling rate in the weak sideband coupling regime and provide an approximate estimate for cooling rates beyond this regime, without the need for explicit simulation of the motional degree of freedom. We clarify the connection between the cooling rate and the absorption spectrum, offering a pathway for efficient near-ground-state cooling of ions with complex electronic structures.

physics.atom-ph

Engineering spin-spin interactions with optical tweezers in trapped ions

We propose a new method for generating programmable interactions in one- and two-dimensional trapped-ion quantum simulators. Here we consider the use of optical tweezers to engineer the sound-wave spectrum of trapped ion crystals. We show that this approach allows us to tune the interactions and connectivity of the ion qubits beyond the power-law interactions accessible in current setups. We demonstrate the experimental feasibility of our proposal using realistic tweezer settings and experimentally relevant trap parameters to generate the optimal tweezer patterns to create target spin-spin interaction patterns in both one- and two-dimensional crystals. Our approach will advance quantum simulation in trapped-ion platforms as it allows them to realize a broader family of quantum spin Hamiltonians.

quant-ph