Quantum computers cant teleport thingsyet

Date:
Fri, 07 Apr 2023 12:28:09 +0000

Description:
Google's Sycamore quantum computer processor was recently at the center of a hotly debate wormhole simulation. Rocco Ceselin/Google It's almost impossible to simulate a good wormhole without more qubits. The post Quantum computers cant teleport thingsyet appeared first on Popular Science .

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Google's Sycamore quantum computer processor was recently at the center of a hotly debate wormhole simulation. Rocco Ceselin/Google

Last November, a group of physicists claimed theyd simulated a wormhole for the first time inside Googles Sycamore quantum computer . The researchers tossed information into one batch of simulated particles and said they
watched that information emerge in a second, separated batch of circuits.

It was a bold claim. Wormholes tunnels through space-time are a very theoretical product of gravity that Albert Einstein helped popularize . It would be a remarkable feat to create even a wormhole facsimile with quantum mechanics, an entirely different branch of physics that has long been at odds with gravity.

And indeed, three months later, a different group of physicists argued that the results could be explained through alternative, more mundane means. In response, the team behind the Sycamore project doubled down on their results.

Their case highlights a tantalizing dilemma. Successfully simulating a wormhole in a quantum computer could be a boon for solving an old physics conundrum, but so far, quantum hardware hasnt been powerful or reliable
enough to do the complex math. Theyre getting there very quickly, though.

[Related: Journey to the center of a quantum computer ]

The root of the challenge lies in the difference of mathematical systems. Classical computers, such as the device youre using to read this article, store their data and do their computations with bits, typically made from silicon. These bits are binary: They can be either zero or one, nothing else.

For the vast majority of human tasks, thats no problem. But binary isnt ideal for crunching the arcana of quantum mechanics the bizarre rules that guide
the universe at the smallest scalesbecause the system essentially operates in a completely different form of math.

Enter a quantum computer, which swaps out the silicon bits for qubits that adhere to quantum mechanics. A qubit can be zero, oneor, due to quantum trickery, some combination of zero and one. Qubits can make certain calculations far more manageable. In 2019, Google operators used Sycamores qubits to complete a task in minutes that they said would have taken a classical computer 10,000 years.

There are several ways of simulating wormholes with equations that a computer can solve. The 2022 papers researchers used something called the SachdevYeKitaev (SYK) model. A classical computer can crunch the SYK model , but very ineffectively. Not only does the model involve particles interacting at a distance, it also features a good deal of randomness, both of which are tricky for classical computers to process.

Even the wormhole researchers greatly simplified the SYK model for their experiment. The simulation they did, actually, is very easy to do
classically, says Hrant Gharibyan , a physicist at Caltech, who wasnt
involved in the project. I can do it in my laptop.

But simplifying the model opens up new questions. If physicists want to show that theyve created a wormhole through quantum math, it makes it harder for them to confirm that theyve actually done it. Furthermore, if physicists want to learn how quantum mechanics interact with gravity, it gives them less information to work with.

Critics have pointed out that the Sycamore experiment didnt use enough
qubits. While the chips in your phone or computer might have billions or trillions of bits, quantum computers are far, far smaller. The wormhole simulation, in particular, used nine.

While the team certainly didnt need billions of qubits, according to experts, they should have used more than nine. With a nine-qubit experiment, youre not going to learn anything whatsoever that you didnt already know from classically simulating the experiment, says Scott Aaronson , a computer scientist at the University of Texas at Austin, who wasnt an author on the paper.

If size is the problem, then current trends give physicists reason to be optimistic that they can simulate a proper wormhole in a quantum computer. Only a decade ago, even getting one qubit to function was an impressive feat. In 2016, the first quantum computer with cloud access had five. Now, quantum computers are in the dozens of qubits. Google Sycamore has a maximum of 53. IBM is planning a line of quantum computers that will surpass 1,000 qubits by the mid-2020s.

Additionally, todays qubits are extremely fragile. Even small blips of noise or tiny temperature fluctuationsqubits need to be kept at frigid
temperatures, just barely above absolute zeromay cause the medium to
decohere, snapping the computer out of the quantum world and back into a mundane classical bit. (Newer quantum computers focus on trying to make
qubits cleaner.)

Some quantum computers use individual particles; others use atomic nuclei . Googles Sycamore, meanwhile, uses loops of superconducting wire . It all
shows that qubits are in their VHS-versus-Betamax era: There are multiple competitors, and it isnt clear which qubitif anywill become the equivalent to the ubiquitous classical silicon chip.

You need to make bigger quantum computers with cleaner qubits, says
Gharibyan, and thats when real quantum computing power will come.

[Related: Scientists eye lab-grown brains to replace silicon-based computer chips ]

For many physicists, thats when great intangible rewards come in. Quantum physics, which guides the universe at its smallest scales, doesnt have a complete explanation for gravity, which guides the universe at its largest. Showing a quantum wormholewith qubits effectively teleportingcould bridge
that gap.

So, the Google users arent the only physicists poring over this problem. Earlier in 2022, a third group of researchers published a paper, listing
signs of teleportation theyd detected in quantum computers . They didnt send
a qubit through a simulated wormholethey only sent a classical bitbut it was still a promising step. Better quantum gravity experiments, such as
simulating the full SYK model, are about purely extending our ability to
build processors, Gharibyan explains.

Aaronson is skeptical that a wormhole will ever be modeled in a meaningful form, even in the event that quantum computers do reach thousands of qubits. Theres at least a chance of learning something relevant to quantum gravity that we didnt know how to calculate otherwise, he says. Even then, Ive struggled to get the experts to tell me what that thing is.

The post Quantum computers cant teleport thingsyet appeared first on Popular Science . Articles may contain affiliate links which enable us to share in
the revenue of any purchases made.



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Link to news story: https://www.popsci.com/technology/wormhole-teleportation-quantum-computer-simu lation/


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