New reports this week show how Microsoft is working to advance the nascent field of quantum computing, in a fundamental way that has to do with how the underlying hardware and data systems of quantum computers are set up.
At the same time that Google and IBM are duking it out over their versions of quantum supremacy (contending that quantum systems are reaching the point where conventional computers can’t catch up,) Microsoft has quietly announced the topological qubit, an engineering feat that opens the door to enhanced quantum work.
So what is a topological qubit?
First, it’s necessary to understand the basics of quantum computing, in which a data structure called a “qubit” replaces the traditional binary bit. Like a bit, a qubit can have a value of either 1 or 0, but in addition, the qubit can also have a superimposed value of a combination of probabilities, an “entangled 1 and 0.”
Now, in order to facilitate this, there are “physical qubits” and “logical qubits.” In a fairly hardware-agnostic way, a physical qubit holds the above three value possibilities. However, physical qubits in current quantum media have issues with decoherence. So, the logical qubit was born.
The logical qubit creates a structure where qubits become more stable. So it is with Microsoft’s new topological qubit, where tying together a range of such individual quantum bits creates more of a “consensus” if you will. In fact, some would say the topological qubit is similar, in a way, to a blockchain.
However, in practical scenarios, more analysts see quantum computing as a threat to blockchain, since quantum computers could hack a conventional blockchain system. So, some propose quantum blockchains. This becomes rather involved, from a scientific viewpoint.
“(The) idea is to create a blockchain using quantum particles that are entangled in time,” wrote anonymous authors at the MIT Technology Review in the spring of 2018, describing how this works. “That would allow a single quantum particle to encode the history of all its predecessors in a way that cannot be hacked without destroying it.”
In order for that to work, though, we would need another technology, a “quantum web,” as explained further on in the same article:
“(A) key part of the infrastructure necessary to make this kind of quantum blockchain work is not yet available: a quantum web. This is a network that can transmit quantum information via quantum routers without destroying its quantum properties. This kind of system is currently being designed and expected to be rolled out in Europe, the US, and China in the coming months or years.”
Getting back to the premise of using new logical qubit constructions, Microsoft now seems to be solidly in the vanguard of work on this disruption. That may have an outsized effect on how quantum computing comes to fruition soon – and it’s likely to lead to some astounding advances in consumer and business technologies within the next few years.