Sycamore is a

quantum processor Quantum computing is a type of computation whose operations can harness the phenomena of quantum mechanics, such as superposition, interference, and entanglement. Devices that perform quantum computations are known as quantum computers. Though ...

created by

Google Google LLC () is an American multinational technology company focusing on search engine technology, online advertising, cloud computing, computer software, quantum computing, e-commerce, artificial intelligence, and consumer electronics. ...

's Artificial Intelligence division. It has 53

qubits In quantum computing, a qubit () or quantum bit is a basic unit of quantum information—the quantum version of the classic binary bit physically realized with a two-state device. A qubit is a two-state (or two-level) quantum-mechanical system, ...

. In 2019, Sycamore completed a task in 200 seconds that Google claimed, in a ''

Nature Nature, in the broadest sense, is the physics, physical world or universe. "Nature" can refer to the phenomenon, phenomena of the physical world, and also to life in general. The study of nature is a large, if not the only, part of science. ...

'' paper, would take a state-of-the-art supercomputer 10,000 years to finish. Thus, Google claimed to have achieved

quantum supremacy In quantum computing, quantum supremacy or quantum advantage is the goal of demonstrating that a programmable quantum device can solve a problem that no classical computer can solve in any feasible amount of time (irrespective of the usefulness of ...

. To estimate the time that would be taken by a classical supercomputer, Google ran portions of the quantum circuit simulation on the

Summit A summit is a point on a surface that is higher in elevation than all points immediately adjacent to it. The topography, topographic terms acme, apex, peak (mountain peak), and zenith are synonymous. The term (mountain top) is generally used ...

, the most powerful classical computer in the world. Later, IBM made a counter-argument, claiming that the task would only take 2.5 days on a classical system like Summit. If Google's claims are upheld, then it would represent an exponential leap in computing power. In August 2020, quantum engineers working for Google reported the largest chemical simulation on a quantum computer – a Hartree–Fock approximation with Sycamore paired with a classical computer that analyzed results to provide new parameters for the 12-qubit system. In April 2021, researchers working with Sycamore reported that they were able to realize the ground state of the

toric code The toric code is a topological quantum error correcting code, and an example of a stabilizer code, defined on a two-dimensional spin lattice. It is the simplest and most well studied of the quantum double models. It is also the simplest example of ...

, a topologically ordered state, with 31 qubits. They showed long-range entanglement properties of the state by measuring non-zero

topological entropy In mathematics, topology (from the Greek words , and ) is concerned with the properties of a geometric object that are preserved under continuous deformations, such as stretching, twisting, crumpling, and bending; that is, without closing h ...

, simulating

anyon In physics, an anyon is a type of quasiparticle that occurs only in two-dimensional systems, with properties much less restricted than the two kinds of standard elementary particles, fermions and bosons. In general, the operation of exchangi ...

interferometry and their braiding statistics, and preparing a topological

quantum error correcting code Quantum error correction (QEC) is used in quantum computing to protect quantum information from errors due to decoherence and other quantum noise. Quantum error correction is theorised as essential to achieve fault tolerant quantum computing that ...

with one logical qubit. In July 2021, a collaboration consisting of Google and multiple universities reported the observation of a discrete

time crystal In condensed matter physics, a time crystal is a quantum system of particles whose lowest-energy state is one in which the particles are in repetitive motion. The system cannot lose energy to the environment and come to rest because it is alre ...

on the Sycamore processor. The chip of 20 qubits was used to obtain a

many-body localization Many-body localization (MBL) is a dynamical phenomenon occurring in isolated many-body quantum systems. It is characterized by the system failing to thermalization, reach thermal equilibrium, and retaining a memory of its initial condition in lo ...

configuration of up and down spins. The configuration was stimulated with a laser to achieve a periodically driven " Floquet" system where all up spins are flipped for down and vice versa in periodic cycles which are multiples of the laser's cycles. No energy was absorbed from the laser so the system remained in a protected eigenstate order. In 2022, the Sycamore processor was used to simulate traversable wormhole dynamics.

References

{{reflist Artificial intelligence laboratories Supercomputers Quantum computing Google hardware