Chief technology officer of Pasqual: analog quantum computing takes the lead in bringing quantum advantages to industry

Long before digital computers swept the world , Analog computers have already provided services for human beings . Now? , The essence of quantum physics is making us re-examine the difference between digital and analog . image Pasqal In this way Quantum hardware enterprises are “ hug ” This duality , By developing hybrid digital / Simulation solutions , To accelerate the realization of industrial quantum advantages .

Digital and analog computing

The wonderful thing about computers is , It can turn questions into answers . Human beings have used computers for thousands of years ： As early as BC 2 century , The ancient Greeks used manual computers （Antikythera Computing machine ） To predict astronomical positions and solar eclipses .

therefore , What makes today's computers different ？ Why does quantum computing need to take into account this duality ？

First , It takes a certain amount of time for computers to calculate problems , The whole process includes continuous type and discrete type , Thus, there is a distinction between analog and digital . At present , Numerical calculation is the main method , It has even become a synonym for Computing . Digital computing dominates , There are several reasons ： Versatility and fault tolerance .

And in the 1960 Years ago , The two calculation methods are in the same position .

Analog computing has brought computing advantages to mankind earlier than digital computers . For example, in 1836 year , French mathematician Gaspard-Gustave Coriolis An analog computer for solving differential equations was introduced . These computers are 19 Century and 20 It continued to develop at the beginning of the century , And began to be used to predict tides and projectile trajectories . from 1960 Year to 1984 year ,Deltar Analog computer （ chart 1） For design and implementation Delta Works Large infrastructure projects , The project aims to protect densely populated areas in the Netherlands from maritime threats .

 

Deltar Analog computer

Reexamine simulation calculation with quantum

Quantum computers are also divided into two forms, digital and analog ： In digital quantum computing , We implement discrete sequences of operations （ It is usually called quantum gate ） To execute the algorithm ; On the quantum computing simulator , The user can control a few parameters , Keep approaching the answer .

The reason why classical computing moves towards digitalization , One of the main reasons is fault tolerance . This is because “ rounding ” Rules can eliminate small mistakes , Such as 0.99 Be regarded as 1,0.002 Be regarded as 0, Bit is very robust to small errors . Besides , Every possible calculation can be written in numerical operation , in other words , Digital computers are universal .

In classical calculations , Analog computers are used to solve specific tasks . Put aside the characteristics , Analog computers can be used as powerful and energy-saving accelerators .

Besides , The characteristics of analog and digital are more subtle in the quantum field . Continuity and discreteness are inextricably linked in quantum systems , Typical wave particle duality . Qubits are analog objects , Until they are measured and turned into numbers . This means quantum computers （ Even digital computers ）, It can also maintain the characteristics of simulation . We believe that , Quantum computers should accept this duality and use it as a resource .

Numbers / Simulate duality

Those with double digits / Neutral atom quantum processor with simulation capability , The calculation follows three main steps ： First , The input information is encoded into an array of neutral atoms ; then , The information is processed by a tuned laser ; And then by taking pictures of atoms “ picture ” To read the final state , To extract the calculation results . Neutral atom computers can be written in numbers / Simulation mode or a combination of these two modes runs the processing steps , So in the near future / Realize quantum advantages in the long run .

The main advantage of digital methods is versatility . Every possible operation on a quantum computer can be represented as a （ Limited ） Gate sequence . The problem is , Today's quantum computers can only execute very short sequences before the results become unreliable .

This is because a single door is noisy and error complex . therefore , Even large （ Multiple qubits ） The capabilities of digital quantum computers are also very limited . by comparison , The versatility of simulation mode is slightly poor , But it is not easily affected by noise . So just like the development of classical computing , Quantum simulation is expected to bring Early Quantum advantages in specific but critical applications .

It needs to be emphasized here , This method is different from the more restrictive simulation method of quantum annealing .

Quantum annealing as a computational paradigm , Can solve specific types of problems , Such as optimization problems . although , In theory , Any problem can be transformed into an optimization problem , But quantum annealing is more suitable for tasks that already have this form . The tasks that can be performed by the simulation of neutral atom quantum computer are far more than these ： In addition to optimizing tasks , Including Chemistry 、 Physics and material engineering . Besides , It can also be combined with digital gate （ Digital analog method ）.

Simulate quantum advantages

The simulation mode of neutral atom quantum computer embodies Richard · Feynman uses synthetic quantum systems to simulate natural dreams . Now? , In terms of simulating physical systems , Neutral atom quantum computers have gone beyond classical simulation ： They have been used to simulate antiferromagnetism in two-dimensional materials , And a programmable simulator for two iconic quantum magnetic models .

These achievements are based on the scalability of neutral atom quantum processors and the fault tolerance advantages of simulation modes ： Hundreds of qubits can be effectively operated in analog mode 、 Realize a variety of simulation operations .

There are several neutral atom quantum hardware manufacturers in the world , Such as Pasqal、QuEra Computing、ColdQuanta and Atom Computing, They are taking measures to bring quantum advantages to industrial applications , Including those who are studying simulation methods Pasqal、 Study door method Atom etc. .

One of the most promising directions is to solve differential equations . In order to advance the plan ,Pasqal A powerful differential equation solver compatible with recent quantum hardware is introduced , And in the paradigm engineering problem （ Such as modeling structural integrity ） It was tested in .

Interestingly , When mixed numbers / When the simulation mode is executed , The performance of the solver has been improved . When single qubit gates are used to adjust and guide output solutions , Multiple qubits are manipulated to achieve “ entanglement ” Power .

In digital mode , These entanglement operations are decomposed into a large number of double qubit gates . However , In a simulated environment , The natural interaction between atoms can effectively entangle them in a short time , And reduce the error , The whole system effectively develops towards the desired results .

Differential equations play a crucial role in many industries . therefore , Quantum advantage has a huge impact in this field .

Neutral atom quantum computer is relying on simulation mode to realize quantum enhanced machine learning technology . up to now , Their focus is on graph related issues , For example, quantum computing company QuEra The promising results of solving the maximum independent set problem are published , The problem lies in telecommunications 、 It is widely used in finance, logistics and other industries .

Pasqal It shows how to use quantum evolutionary kernel method （Quantum evolution kernel,QEK） The simulated quantum method in solves the problem of graph classification , This method is proved to be superior to the classical kernel method in accuracy and computational cost .Pasqal It also puts forward QEK The first application in the toxicity screening of compounds , They are studying applications to determine the best chemical reaction route .

today ,Pasqal Entanglement and manipulation can be achieved using hundreds of qubits in analog mode , And use this ability to solve many exciting problems .

More and more quantum hardware manufacturers are embracing the simulation of quantum computers / Digital dual characteristics , Learn from history ,Pasqal It is believed that analog quantum computers are bringing quantum advantages .

Link to the original text ：

https://thequantuminsider.com/2022/06/28/why-analog-neutral-atoms-quantum-computing-is-a-promising-direction-for-early-quantum-advantage/

writing ：Loïc Henriet（CTO, Pasqal）

compile ： Li every

edit ： Mu Yi

notes ： Ben Translated from “thequantuminsider”, Do not represent Quantum outpost view .

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