Physicists take big step in race to quantum computing: Team develops simulator with 256 qubits, largest of its kind ever created

A group of physicists from the Harvard-MIT Middle for Ultracold Atoms and different universities has developed a particular sort of quantum laptop often known as a programmable quantum simulator able to working with 256 quantum bits, or “qubits.”

The system marks a significant step towards constructing large-scale quantum machines that might be used to make clear a bunch of complicated quantum processes and ultimately assist result in real-world breakthroughs in materials science, communication applied sciences, finance, and lots of different fields, overcoming analysis hurdles which can be past the capabilities of even the quickest supercomputers right this moment. Qubits are the elemental constructing blocks on which quantum computer systems run and the supply of their huge processing energy.

“This strikes the sphere into a brand new area the place nobody has ever been to to date,” mentioned Mikhail Lukin, the George Vasmer Leverett Professor of Physics, co-director of the Harvard Quantum Initiative, and one of many senior authors of the research revealed right this moment within the journal Nature. “We’re coming into a totally new a part of the quantum world.”

In response to Sepehr Ebadi, a physics scholar within the Graduate College of Arts and Sciences and the research’s lead writer, it’s the mixture of system’s unprecedented measurement and programmability that places it on the chopping fringe of the race for a quantum laptop, which harnesses the mysterious properties of matter at extraordinarily small scales to drastically advance processing energy. Below the appropriate circumstances, the rise in qubits means the system can retailer and course of exponentially extra data than the classical bits on which customary computer systems run.

“The variety of quantum states which can be potential with solely 256 qubits exceeds the variety of atoms within the photo voltaic system,” Ebadi mentioned, explaining the system’s huge measurement.

Already, the simulator has allowed researchers to watch a number of unique quantum states of matter that had by no means earlier than been realized experimentally, and to carry out a quantum section transition research so exact that it serves because the textbook instance of how magnetism works on the quantum degree.


These experiments present highly effective insights on the quantum physics underlying materials properties and will help present scientists the best way to design new supplies with unique properties.

The venture makes use of a considerably upgraded model of a platform the researchers developed in 2017, which was able to reaching a measurement of 51 qubits. That older system allowed the researchers to seize ultra-cold rubidium atoms and organize them in a particular order utilizing a one-dimensional array of individually targeted laser beams known as optical tweezers.

This new system permits the atoms to be assembled in two-dimensional arrays of optical tweezers. This will increase the achievable system measurement from 51 to 256 qubits. Utilizing the tweezers, researchers can organize the atoms in defect-free patterns and create programmable shapes like sq., honeycomb, or triangular lattices to engineer completely different interactions between the qubits.

“The workhorse of this new platform is a tool known as the spatial gentle modulator, which is used to form an optical wavefront to provide a whole bunch of individually targeted optical tweezer beams,” mentioned Ebadi. “These gadgets are basically the identical as what’s used inside a pc projector to show photos on a display, however we now have tailored them to be a crucial part of our quantum simulator.”

The preliminary loading of the atoms into the optical tweezers is random, and the researchers should transfer the atoms round to rearrange them into their goal geometries. The researchers use a second set of shifting optical tweezers to tug the atoms to their desired areas, eliminating the preliminary randomness. Lasers give the researchers full management over the positioning of the atomic qubits and their coherent quantum manipulation.


Different senior authors of the research embrace Harvard Professors Subir Sachdev and Markus Greiner, who labored on the venture together with Massachusetts Institute of Know-how Professor Vladan Vuleti?, and scientists from Stanford, the College of California Berkeley, the College of Innsbruck in Austria, the Austrian Academy of Sciences, and QuEra Computing Inc. in Boston.

“Our work is a part of a extremely intense, high-visibility world race to construct greater and higher quantum computer systems,” mentioned Tout Wang, a analysis affiliate in physics at Harvard and one of many paper’s authors. “The general effort [beyond our own] has prime tutorial analysis establishments concerned and main private-sector funding from Google, IBM, Amazon, and lots of others.”

The researchers are presently working to enhance the system by enhancing laser management over qubits and making the system extra programmable. They’re additionally actively exploring how the system can be utilized for brand new purposes, starting from probing unique types of quantum matter to fixing difficult real-world issues that may be naturally encoded on the qubits.

“This work permits an enormous variety of new scientific instructions,” Ebadi mentioned. “We’re nowhere close to the bounds of what might be carried out with these techniques.”

This work was supported by the Middle for Ultracold Atoms, the Nationwide Science Basis, the Vannevar Bush School Fellowship, the U.S. Division of Power, the Workplace of Naval Analysis, the Military Analysis Workplace MURI, and the DARPA ONISQ program.