Stanford engineers have revealed a new, simplified quantum structure in which a single atom entangled with a series of photons is used to process and store information.
“We only need a few relatively basic ingredients”
Quantum computers take advantage of the strange world of quantum physics to perform much faster calculations than conventional computers. While the latter stores and processes information in the form of bits (1 and 0), those of quantum machines are called qubit, can exist in a simultaneous superposition of these two states. This means that their power increases exponentially with each qubit added, allowing them to tackle problems that are beyond the capacity of traditional computers.
Of course, quantum computers present their own challenges. The impacts on which they are based are sensitive to disturbances such as vibration or heat, so these machines must be kept at temperatures close to absolute zero. With complexity commensurate with their computing power, they become more physically complex as their capabilities increase.
In the context of the work published in the magazine Visual, Team stanford Imagine a simplified quantum structure. By integrating the common components (fiber-optic cable, bundle splitter, switches and optical cavity), the described optical circuit allows to reduce the number of physical logic gates wanted.
« Normally, to build this kind of machine, you would have to take thousands of potential quantum emitters and then combine them into a giant photonic circuit. ‘, he explains Ben Bartlett, lead author of the study. ” With this design, we only need a relatively few basic components, and the size of the device is no longer proportional to the complexity of the program being executed.. »
simplified photonic circuit
The new architecture consists of two main parts: a ring that stores Photons broadcast unit. Here the photons are qubits, and the direction in which they move around the ring determines whether their value is one, zero, or both (when they go both directions simultaneously, thanks to the quirks of the superposition quantum).
To encode information about the photons, the system can direct them out of the loop into the scattering unit, where they enter a cavity containing a single atom. When a photon interacts with an atom, they become entangled, and any change in one affects the other, regardless of the distance between them.
Practically speaking, once a photon returns to the storage ring, it can be ” writing By treating corns with a laser. The team claims that the latter can be reset and reused, allowing many different photons to be processed in a single loop. This means that the power of the quantum computer can be increased by adding more photons to the ring, rather than having to add more rings and scattering units.
« By measuring the state of the atom, we can transmit remote processes on photons “, details Bartlett. « So we only need one controllable atomic qubit, which is used as a proxy to indirectly deal with all the other qubit photons.. »
Main advantages
Such a system must be able to perform a variety of quantitative operations. The team says they can run different programs on the same circuit, and write new code to change how and when the atom and photons interact.
« For many optical quantum computers, gates are physical structures through which photons pass, so if you want to change the running software, that often involves physically reconfiguring the hardware. ‘, he explains Bartlett. « Here there is no need to change the device, just give the device a different set of instructions. »
Even better, optical quantum devices can operate at room temperature, eliminating the need for massive cooling systems that would otherwise be required.
