September 23, 2023
What is QPU?  |  NVIDIA Blogs

Similar to GPUs and DPUs allow accelerated computing at present, they’re additionally serving to a brand new sort of chip, the QPU. quantum computing.

In your fingers, a quantum computing unit can feel and appear similar to a graphics or knowledge processing unit. They’re all sometimes chips or modules containing a number of chips, however underneath the hood the QPU is a really totally different beast.

So, what’s a QPU?

A QPU, often known as a quantum processor, is the mind of a quantum pc that makes use of the conduct of particles corresponding to electrons or photons to carry out sure kinds of calculations a lot quicker than processors in at present’s computer systems.

QPUs depend on behaviors corresponding to superposition, a particle’s capability to be in lots of states without delay, described within the comparatively new department of physics referred to as quantum mechanics.

In distinction, CPUs, GPUs, and DPUs all apply the rules of classical physics to electrical currents. For that reason, at present’s programs are referred to as classical computer systems.

QPUs can advance cryptography, quantum simulations, and machine studying and clear up difficult optimization issues.

quantum computing models graphics processing models
Primarily based on quantum physics Primarily based on classical physics
Makes use of qubits that may be greater than 0 and 1 Makes use of bits 0 or 1
Makes use of states of subatomic particles Makes use of electrical energy switched in transistors
Nice for simulating cryptography and quantum results Nice for HPC, AI and basic simulations

How Does a Quantum Processor Work?

CPUs and GPUs calculate bits, on/off states {of electrical} present that symbolize zeros or ones. In distinction, QPUs acquire their distinctive energy by computing in qubits, that are quantum bits that may symbolize many various quantum states.

Qubit is an abstraction that pc scientists use to specific knowledge primarily based on the quantum state of a particle in a QPU. Just like the fingers of a clock, qubits seek advice from quantum states, just like factors in a sphere of possibilities.

The facility of a QPU is often outlined by the variety of qubits it comprises. Researchers are growing extra methods to check and measure the general efficiency of a QPU.

Many Methods to Make Qubits

Institutional and educational researchers use all kinds of methods to assemble qubits inside a QPU.

The most well-liked method as of late is known as the superconducting qubit. It’s mainly manufactured from a number of small metallic sandwiches, referred to as Josephson junctions, the place electrons tunnel by way of an insulating layer between two superconducting supplies.

Qubits in IBM's Eagle QPU
Qubits inside IBM’s Eagle superconducting QPU.

The present state-of-the-art generates greater than 100 of those connections in a single QPU. Quantum computer systems utilizing this method isolate electrons by cooling them to near-absolute temperatures with highly effective fridges that resemble high-tech chandeliers. (See picture beneath.)

A Qubit of Gentle

Some corporations use photons as an alternative of electrons to create qubits of their quantum processors. These QPUs do not require costly, power-hungry fridges, however they do want superior lasers and beam splitters to handle photons.

Quantum processor for refrigerator
A cooling unit for a superconducting quantum pc.

Researchers are utilizing and inventing different methods to construct and join qubits inside QPUs. For instance, some use an analog course of referred to as quantum annealing, however programs utilizing these QPUs have restricted functions.

It is early days for quantum computer systems, so it is not but clear what sort of qubits will likely be broadly utilized in what sort of QPUs.

Easy Chips, Unique Programs

Theoretically, QPUs could require much less energy and generate much less warmth than standard processors. Nevertheless, the quantum computer systems they set up might be considerably power-hungry and costly.

It is because quantum programs sometimes require specialised digital or optical management subsystems to exactly manipulate particles. Most require vacuum enclosures, electromagnetic shielding or superior fridges to create the correct atmosphere for particles.

A QPU on a full D-Wave quantum computer
D-Wave exhibits qubits and QPU in a whole system.

That is one cause why quantum computer systems are anticipated to stay primarily in supercomputing facilities and huge knowledge facilities.

QPUs Do Nice Issues

Researchers anticipate QPUs inside quantum computer systems to yield stunning outcomes, thanks to stylish science and expertise. They’re significantly enthusiastic about 4 promising potentialities.

First, they will take pc safety to a complete new stage.

Quantum processors can shortly issue monumental numbers, a basic operate in cryptography. This implies they will break at present’s safety protocols, but in addition create new, rather more highly effective protocols.

Moreover, QPUs are perfect for simulating the quantum mechanics of how objects work on the atomic stage. This might result in basic advances in chemistry and supplies science, initiating domino results in every part from the design of lighter plane to more practical medicine.

The researchers additionally hope that quantum processors will clear up optimization issues that classical computer systems can’t deal with in areas corresponding to finance and logistics. Lastly, they will even advance machine studying.

So, When Will QPUs Be Accessible?

For quantum researchers, QPUs cannot come early sufficient. However challenges run the gamut.

On the {hardware} stage, QPUs are usually not but highly effective or dependable sufficient to deal with most real-world duties. Nevertheless, early QPUs—and GPUs that simulate them with software program like NVIDIA cuQuantum — starting to indicate outcomes that assist researchers, particularly in initiatives investigating find out how to construct higher QPUs and enhance quantum algorithms.

Researchers use prototype programs supplied by corporations corresponding to Amazon, IBM, IonQ, Rigetti, Xanadu and extra. Governments world wide are beginning to see the promise of the expertise, so they’re investing closely in constructing bigger and extra formidable programs.

How Do You Program a Quantum Processor?

Quantum computing software program continues to be in its infancy.

A lot of it appears like meeting language code, the type that programmers needed to cope with within the early days of classical computer systems. Due to this fact, builders want to grasp the main points of the underlying quantum {hardware} to run their applications.

However right here, too, there are actual indicators of progress in the direction of the holy grail – a single software program atmosphere to run on any supercomputer, a sort of quantum working system.

A number of early initiatives are underneath development. All of them battle with the restrictions of present {hardware}; some are blocked by the boundaries of the businesses that developed the code.

For instance, some corporations have deep experience in enterprise computing however lack expertise in high-performance environments the place a lot of the scientific and technical work in quantum computing could be executed. Others lack experience in synthetic intelligence, which has synergies with quantum computing.

Enter Hybrid Quantum Programs

The analysis group broadly agrees that classical and quantum computer systems will work collectively for the foreseeable future. Due to this fact, the software program also needs to run properly on QPUs, CPUs and GPUs.

Diagram of a QPU inside a quantum computer from the 2017 article
Researchers describe a hybrid classical quantum pc in a 2017 paper.

To drive quantum computing ahead, NVIDIA not too long ago launched NVIDIA Quantum Optimized Device Architecture (QODA) is an open platform for programming hybrid quantum programs.

QODA consists of high-level language that’s concise and significant to be highly effective and simple to make use of. With QODA, builders can write applications that run on QPUs in quantum computer systems and GPUs that simulate QPUs in classical programs.

QODA programming software for QPUs
NVIDIA QODA offers builders with a unified platform to program any hybrid quantum-classical pc.

QODA will help any sort of quantum pc and any sort of QPU.

At launch, quantum system and software program suppliers together with Pasqal, Xanadu, QC Ware and Zapata have expressed help for QODA. Customers embrace main supercomputing facilities within the US and Europe.

QODA builds on NVIDIA’s in depth experience in CUDA software program that accelerates HPC and AI workloads for scientific, technical, and enterprise customers.

With the QODA beta anticipated earlier than the tip of the 12 months, the outlook for QPUs in 2023 and past is shiny.

—Yunchao Liu, Ph.D. A quantum computing candidate on the College of California at Berkeley helped analysis this paper.

Be taught extra about quantum computing at: NVIDIA Tech Blog.


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