arXiv subjects

Pedro Ildefonso

Publications and source records attributed to Pedro Ildefonso.

3 recordsLinked to original sources

arXiv2025

Expanding the Neutral Atom Gate Set: Native iSWAP and Exchange Gates from Dipolar Rydberg Interactions

We present a native realization of iSWAP and parametrized \textit{exchange} gates for neutral-atom quantum processing units. Our approach leverages strong dipole-dipole interactions between two different dipole-coupled Rydberg states, employing optimal control techniques to design high-fidelity, time-efficient gate pulses. To minimize experimental complexity, we utilize global driving fields acting identically on all atoms and apply pulse smoothing techniques. While detrimental van der Waals interactions pose a significant challenge, we demonstrate that for both $^{133}$Cs, as a representative alkali atom, and $^{88}$Sr, an alkaline-earth species, high-fidelity pulses can nevertheless be obtained over a broad range of parameters. We identify candidate protocols with reduced susceptibility to noise and analyze their performance under realistic conditions, accounting for atomic motion, Rydberg decay, and experimentally motivated laser frequency and intensity noise. Crucially, we demonstrate that in both Alkali and alkaline-earth-based systems, we can obtain fast iSWAP gates with fidelities of $99.9\%$ under realistic experimental conditions. These results pave the way for expanding the neutral-atom gate set beyond conventional Rydberg-blockade-based entangling gates.

quant-ph↗

arXiv2024

Quantum optimization with globally driven neutral atom arrays

Neutral atoms trapped in configurable tweezer arrays are a promising platform for solving hard optimization problems. While such platforms natively embed unit-disk maximum weight independent set (UD-MWIS) problems, general problem classes require an embedding that maps them onto UD-MWIS instances. Implementing the necessary asymmetric weights has so far required local control of detunings at each atom. Here, we demonstrate quantum optimization using strictly global driving fields, eliminating the need for local field control. Instead, to effectively implement the required local detunings we exploit weak Rydberg interactions---too weak to generate Rydberg blockade but strong enough to effectively induce the required local detunings. For this, we introduce the concept of precisely placed anchor atoms that impose controlled energy shifts on nearby atoms which can be effectively considered as induced local detunings. We demonstrate that parity-architecture-based neutral atom embeddings of general optimization problems allow for a successful anchor placement strategy, such that all demanded local fields can be replaced by anchors. We experimentally demonstrate this concept on a Pasqal Orion Alpha machine and benchmark all standard building blocks. Finally, we solve quadratic unconstrained binary optimization (QUBO) problems on four-node all-to-all connected graphs embedded in a 43-atom array using seven precisely-placed anchor atoms. By removing the requirement for local addressing, our work overcomes a major experimental bottleneck in solving optimization problems on neutral-atom quantum hardware and can be readily integrated into existing platforms.

quant-ph↗

arXiv2023

Self-interacting dipolar boson stars and their dynamics

We construct and dynamically evolve dipolar, self-interacting scalar boson stars in a model with sextic (+ quartic) self-interactions. The domain of existence of such dipolar $Q$-stars has a similar structure to that of the fundamental monopolar stars of the same model. For the latter it is structured in a Newtonian plus a relativistic branch, wherein perturbatively stable solutions exist, connected by a middle unstable branch. Our evolutions support similar dynamical properties of the dipolar $Q$-stars that: 1) in the Newtonian and relativistic branches are dynamically robust over time scales longer than those for which dipolar stars without self-interactions are seen to decay; 2) in the middle branch migrate to either the Newtonian or the relativistic branch; 3) beyond the relativistic branch decay to black holes. Overall, these results strengthen the observation, seen in other contexts, that self-interactions can mitigate dynamical instabilities of scalar boson star models.

gr-qc↗