Rigetti Announces 80-Qubit Quantum Processor and Qutrit Experiments

80-Qubit Quantum Processor

Just the other day, representatives  of the Rigetti company , whose field of activity lies in the field of quantum computing, announced the development of new and very interesting hardware. Note that at the current time the company already provides its customers with remote access to the Aspen-11 quantum processor, which has 40 qubits. And very soon, select customer testers will have access to the next-generation processor, which will technically consist of two new 40-qubit chips that are linked together with improved performance.

In addition, representatives of the Rigetti company reported on experiments that use the third energy quantum state, which turns traditional qubits into  so-called qutrites.... And if the company's specialists manage to ensure the stability of these kutrites, they can process much more data and ensure the execution of more complex quantum algorithms on the same hardware.

As our regular readers know well, one of the most critical parameters of any quantum computing system is the error rate, which reflects how often processor qubits can lose their quantum state due to the phenomenon of so-called quantum decoherence. From this point of view, the new Aspen-M quantum processor demonstrates twice the error rate on read operations of the state of qubits than its predecessor, the Aspen-11 processor.

In terms of the analogy of the clock frequency, the speed of signal transmission, prompting the qubits to perform individual operations, the Aspen-M processor demonstrates a 2.5x speedup compared to the Aspen-11 processor. This also has a positive effect on the efficiency of the system as a whole; during the time after which the qubits lose their state, the new processor will be able to perform more operations or process more data.

But the most important achievement of Rigetti specialists in all this, of course, is a new way of combining several quantum processors into a single whole, the practical implementation of which is associated with many technical problems. If this new method proves its efficiency and effectiveness in practice, it will become that lifesaver that will quickly and cost-effectively increase the number of qubits of quantum computing systems.

Let's return to the experiments of the company's specialists with kutrites. Almost all hardware of existing quantum systems is built on the basis of already traditional quantum bits, qubits, which can be in two quantum states (0 and 1) and in a state of quantum superposition - the simultaneous presence of a qubit in two states. Qutrite, unlike a qubit, can be in three basic states, 0, 1 and 2, and in a state of superposition, which can contain any of the possible combinations of two or three basic values, which significantly increases the information capacity.

However, the practical implementation of kutrit is associated with problems pertaining to the energy levels of each state. If states 0 and 1 have a large enough difference in the energy of a qubit or kutrit, then states 1 and 2 are separated by much less energy. This, in turn, complicates the process of determining the state of a qubit or qutrit, this process is more influenced by thermal and other noises, and the procedure for setting the initial state of qutrit should work much more accurately than the procedure for setting the state of a qubit.

But Rigetti seems to have solved all of the problems mentioned above by making some minor changes to the design of the qubits and changing the monitoring software to handle the third, highest-energy state. Now it only remains to wait for real users to try to use all the benefits of kutrit in practice, and this will show how useful this innovation can be, given the level of development of modern quantum hardware and software.