White paper: Quantum Computing with Neutral Atoms

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We just released our technical white paper, an in-depth description of our technology and our full stack, from atoms to application layer.

Pasqal quantum stack and metrics to evaluate the performances of the quantum processor. Applications (top block of the Quantum stack) can be divided into two groups: Quantum Simulation problems that involve the study of a quantum system, and standard computational problems. To solve these problems, the processor developed at Pasqal can be used in a digital way or in an analog way (middle block of the Quantum stack). The low-level part of the stack corresponds to the physical quantum processor.

Review: Many-body physics with individually controlled Rydberg atoms

Antoine Browaeys and Thierry Lahaye, co-founders and scientists at Pasqal, review in this paper recent developments in the field of quantum simulation with systems of individually controlled neutral atoms, interacting with each other when excited to Rydberg states. They show how they have emerged as a promising platform for this task, particularly for the simulation of spin systems. They review the techniques necessary for the manipulation of neutral atoms for the purpose of quantum simulation—such as quantum gas microscopes and arrays of optical tweezers—and explain how the different types of interactions between Rydberg atoms allow a natural mapping onto various quantum spin models. We discuss recent achievements in the study of quantum many-body physics in this platform, and some current research directions beyond that.

Experimental platforms for realizing arrays of individually controlled neutral atoms. a: In a quantum gas microscope, a high- numerical-aperture objective is used to observe the fluorescence of ultracold atoms trapped in an optical lattice obtained by interfering several laser beams. 

From the lab: 3D trapping of Rydberg atoms

Zeeman Slower for atoms

PASQAL’s co-founders Thierry Lahaye and Antoine Browaeys and their team at IOGS have published groundbreaking work in Physical Review Letters demonstrating the trapping of single Rydberg atoms in micron-sized, hollow laser traps (called ‘Bottle-beam traps’).

While atoms in their ground state are already cooled down and trapped in 3D light patterns (optical tweezers), so far the Rydberg atoms were not trapped, which was expected to be ultimately a limit for gate fidelities and the available time for coherent dynamics for simulation. Once trapped in the dark region of the trap, using a second set of optical tweezers in 3D,  the Rydberg atoms can be kept for hundreds of microseconds, only limited by their lifetime. The teams shows that trapping does not degrade coherent manipulations of the internal state of the atom using microwave, nor the interaction-induced swapping of internal states between two atoms. These results further extend the possibilities offered by Rydberg atoms arrays for quantum computing.

A summary is provided in the Synopsis section.



BoB trap in 3D

Main components of the experimental setup. The zoom shows two-dimensional cuts of the reconstructed light intensity distribution near the focal plane.

Performance of NISQ algorithms

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Loic Henriet, head of Quantum Software at Pasqal, has published an original research about the robustness of variational algorithms w/r to dissipative processes such as spontaneous emission. This result is an additional element in favor of NISQ computers towards practical applications.