Radical quantum computing theory could lead to more powerful machines than previously imagined

Physicists have created a new model for quantum computers that could more easily scale them up and make them more powerful than previously imagined. 

The new theory, outlined in a study published May 21 in the journal PRX Quantum, proposes linking qubits, the fundamental workhorses of quantum computers, over vast distances to work as if they were part of a single super-powerful machine. 

Where bits are used in classical computing to process data in binary states of 1 or 0, and in sequence, quantum computing uses qubits (which rely on the laws of quantum mechanics) to encode data in a superposition of 1 and 0. This means data can be encoded in both states simultaneously. Each qubit operates in a given frequency.

These qubits can then be stitched together through quantum entanglement — where their data is linked across vast separations over time or space — to process calculations in parallel. The more qubits are entangled, the more exponentially powerful a quantum computer will become. 

Entangled qubits must share the same frequency. But the study proposes giving them "extra" operating frequencies so they can resonate with other qubits or work on their own if needed.

The road to quantum supremacy

With enough entangled qubits, future quantum computers could perform calculations that would have taken a classical computer thousands of years in just a few seconds. But you need a quantum processor with millions of qubits to achieve this state of "quantum supremacy," whereas the most powerful today have just 1,000 qubits.

But maintaining the stability between entangled qubits, so that you can process data, is difficult and requires complex electronics and equipment. Scaling up the qubits in a quantum computer so it's powerful enough to leapfrog today's most powerful supercomputers also represents a major hurdle — as you would also need to scale up that complex circuitry.