A new breakthrough in quantum computing could completely change the cost of computers – BGR

Quantum computers, once thought to be decades away, are now much closer than expected thanks to the work of researchers at the California Institute of Technology and ETH Zurich. Quantum computers are causing a huge stir in the scientific and technical community because they have the potential to outperform standard computers in many fields.

Quantum computing could lead to the discovery of new drugs and treatments (through advanced protein folding and reaction pathway analysis), financial predictive models that could reshape Wall Street, or energy grid optimization that could help alleviate the global energy crisis. Troublingly, they can also break some of the most common existing encryption methods, potentially creating vulnerabilities in industries such as banking and data security.

A breakthrough at the California Institute of Technology shows that practical quantum computers built around just 10,000 to 20,000 qubits, rather than the millions of qubits previously thought necessary, may be possible. This means a quantum platform that is easier to develop and cheaper to manufacture. At the same time, advances by researchers at ETH Zurich show how neutral atom platforms (of the type used in the Caltech study) can prove remarkably error-tolerant, another major hurdle hindering the practical development of quantum computers.

Qubits are the quantum equivalent of bits in traditional computing. However, unlike traditional bits, which can only exist in one of two states (0 or 1), qubits can exist in both states simultaneously. They also have other magical-sounding properties, including what Albert Einstein called “spooky behavior at a distance.” That is, the ability to intertwine with another qubit, even if they are vastly separated, so that changing the state of one instantly changes the state of the other. This means that information can be instantly “teleported” between qubits without any physical connection.

The problem is that qubits are notoriously susceptible to interference such as heat and noise. To address this problem, researchers group large numbers of qubits together to create a single, more stable “logical” qubit that can perform calculations with fewer errors. Unfortunately, a practical quantum computer requires around 1,000 logical qubits, each consisting of around 1,000 physical qubits, for a total of more than 1 million qubits. That’s a big engineering challenge.

A breakthrough from Caltech and Oratomic (a Caltech-affiliated startup) shows that by using neutral atomic qubits, logical qubits can be built from as few as five physical qubits instead of 1,000, by storing information in the internal quantum state of a single, electrically neutral atom that is captured in place by “laser tweezers.”

Meanwhile, on the other side of the world in Switzerland, researchers at ETH Zurich, one of the world’s leading science and technology universities, have discovered a way to perform extremely stable quantum logic operations using qubits made of neutral atoms. One of the key aspects of quantum processing is the ability to shift qubits between the aforementioned 0 and 1 states (or both simultaneously). This is done through swap gates, which allow information to be routed through a quantum system by linking qubits and exchanging states between them.

Previous methods of performing swap gates relied heavily on things like how quickly the laser could be turned on and how precisely the laser’s power level could be controlled. Small fluctuations can cause significant errors in quantum systems. The Zurich team was able to reduce these errors by using a physical effect called “geometric topology.” This kind of phase is less unstable and has fewer errors because it depends only on the geometry of its motion, rather than on variables that are difficult to control, such as the speed of the atom’s movement or the intensity of the laser.

These developments are important in bringing Shor’s algorithm closer to reality. Scholl’s algorithm is a way to factor large integers into their prime components, and could be used to crack widely used cryptographic systems that currently protect oceans of sensitive data. Although Caltech’s breakthrough remains at a theoretical stage for now, the team has already generated an array of more than 6,000 neutral atomic qubits.