Wiring: Overcoming Scalability and Stability in Quantum Computing
Well done work from RIKEN’s team lead, Yasunobu Nakamura. Recommend reading from the source. Because Quantum is Coming. Qubit
Wiring a new path to scalable quantum computing
+ To make larger and more useful systems, most of today’s prototypes will have to overcome the challenges of stability and scalability. The latter will require increasing the density of signaling and wiring, which is hard to do without degrading the system’s stability. I believe a new circuit-wiring scheme developed over the last three years by RIKEN’s Superconducting Quantum Electronics Research Team, in collaboration with other institutes, opens the door to scaling up to 100 or more qubits within the next decade.
Last year, Google produced a 53-qubit quantum computer that could perform a specific calculation significantly faster than the world’s fastest supercomputer. Like most of today’s largest quantum computers, this system boasts tens of qubits—the quantum counterparts to bits, which encode information in conventional computers.
+ Challenge One: Scalability
+ Quantum computers process information using delicate and complex interactions based on the principles of quantum mechanics. To explain this further we must understand qubits. A quantum computer is built from individual qubits, which are analogous to the binary bits used in conventional computers. But instead of the zero or one binary states of a bit, a qubit needs to maintain a very fragile quantum state. Rather than just being zero or one, qubits can also be in a state called a superposition—where they are sort of in a state of both zero and one at the same time. This allows quantum computers based on qubits to process data in parallel for each possible logical state, zero or one, and they can thus perform more efficient, and thus faster, calculations than conventional computers based on bits for particular types of problems.
+ Challenge Two: Stability
+ The other major challenge for quantum computers is how to deal with the intrinsic vulnerability of the qubits to fluctuations or noise from outside forces such as temperature. For a qubit to function, it needs to be maintained in a state of quantum superposition, or ‘quantum coherence’. In the early days of superconducting qubits, we could make this state last for just nanoseconds. Now, by cooling quantum computers to cryogenic temperatures and creating several other environmental controls, we can maintain coherence for up to 100 microseconds. A few hundred microseconds would allow us to perform a few thousand information processing operations, on average, before coherence is lost.
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