Sci­en­tists develop fermionic quan­tum pro­ces­sor

A new type of quantum computer that uses fermionic atoms to simulate complex physical systems.


Fermionic atoms adhere to the Pauli exclusion principle, preventing more than one from simultaneously being in the same quantum state. As a result, they are perfect for modeling systems like molecules, superconductors, and quark-gluon plasmas where fermionic statistics are critical.

Using fermionic atoms, scientists from Austria and the USA have designed a new quantum computer to simulate complex physical systems. The processor uses programmable neutral atom arrays and has hardware-efficient fermionic gates for modeling fermionic models.

The group, under the direction of Peter Zoller, showed how the new quantum processor can simulate fermionic models from quantum chemistry and particle physics with great accuracy.

A fermionic register and several fermionic quantum gates comprise a fermionic quantum processor. The register’s local unit of quantum information comprises a set of fermionic modes that can either be empty or inhabited by a single fermion.

Daniel Gonzalez Cuadra, from the research group led by Peter Zoller at the Institute for Quantum Optics and Quantum Information (IQOQI) of the Austrian Academy of Sciences (ÖAW), said, “The state of the system we want to simulate, such as a molecule composed of many electrons, will be in general a superposition of many occupation patterns, which can be directly encoded into this register.”

“This information is then processed using a fermionic quantum circuit designed to simulate, for example, the time evolution of a molecule. Any such circuit can be decomposed into a sequence of just two types of fermionic gates, a tunneling, and an interaction gate.”

The scientists propose to hold and manipulate fermionic atoms with extreme accuracy in an array of optical tweezers, which are highly concentrated laser beams. The necessary set of fermionic quantum gates can be natively implemented in this platform: interaction gates are implemented by first exciting the atoms to Rydberg states, carrying a strong dipole moment, and tunneling gates are obtained by controlling the tunneling of an atom between two optical tweezers.

Daniel Gonzalez Cuadra said“By using fermions to encode and process quantum information, some properties of the simulated system are intrinsically guaranteed at the hardware level, which would require additional resources in a standard qubit-based quantum computer.”

“I am very excited about the future of the field, and I would like to keep contributing to it by identifying the most promising applications for fermionic quantum processing and by designing tailored algorithms that can run in near-term devices.”

Journal Reference:

  1. Fermionic quantum processing with programmable neutral atom arrays. D. Gonzalez-Cuadra, D. Bluvstein, M. Kalinowski, R. Kaubruegger, N. Maskara, P. Naldesi, T.V. Zache, A. M. Kaufman, M. D. Lukin, H. Pichler, B. Vermersch, Jun Ye, and P. Zoller. PNAS 2023 DOI: 10.1073/pnas.2304294120
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