Figure 1: Schematic diagrams of three types of quantum simulators: atoms (red) held in place by an optical field (green; top left); ions (yellow) aligned using an electromagnetic field (top right); and superconducting circuits (bottom).
Iulia Buluta and Franco Nori of the RIKEN Advanced Science Institute present an overview of how quantum simulators may become a reality in the near future. They pinpoint future directions and argue that the technologies are now within reach.
Science - Quantum Simulators
Quantum simulators are controllable quantum systems that can be used to simulate other quantum systems. Being able to tackle problems that are intractable on classical computers, quantum simulators would provide a means of exploring new physical phenomena. We present an overview of how quantum simulators may become a reality in the near future as the required technologies are now within reach. Quantum simulators, relying on the coherent control of neutral atoms, ions, photons, or electrons, would allow studying problems in various fields including condensed-matter physics, high-energy physics, cosmology, atomic physics, and quantum chemistry.
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Among the various physical systems that could be used to build a quantum simulator, one possibility is the use of regular arrays of atoms or ions that are held in place by laser fields. According to Buluta and Nori, the interactions between these atoms provide a good model for emulating the interaction between other particles in complex systems. To model electrical conductivity, for example, this type of quantum simulator can be used to study the transition from the insulating state to the conducting state, where the atoms switch from being fixed to being free to move.
Buluta and Nori also point out that electronic devices fabricated on a computer chip could be used as a controllable quantum system. In this system, small circuits made from superconducting wires possess quantum physical properties that could be used to model atomic physics problems.
These quantum systems have been demonstrated experimentally; however, challenges remain until more advanced and versatile quantum simulators can be built. Synchronizing the operation of a large number of components, for example, has not yet been achieved, Buluta notes. From a theoretical viewpoint, she says that much also needs to be learned about meaningfully programming quantum simulators.
7 page pdf with supplemental material
Universal Quantum Simulators at wikipedia
Abstract of the Seth Lloyd article on Universal Quantum Simulators and links to articles that cite it