Strange New Phase of Matter Created in Quantum Computer Acts Like It Has Two Time Dimensions:
By shining a laser pulse sequence inspired by the Fibonacci numbers at atoms inside a quantum computer, physicists have created a remarkable, never-before-seen phase of matter. The phase has the benefits of two time dimensions despite there still being only one singular flow of time, the physicists report July 20 in Nature.
This mind-bending property offers a sought-after benefit: Information stored in the phase is far more protected against errors than with alternative setups currently used in quantum computers. As a result, the information can exist without getting garbled for much longer, an important milestone for making quantum computing viable, says study lead author Philipp Dumitrescu.
The approach's use of an "extra" time dimension "is a completely different way of thinking about phases of matter," says Dumitrescu, who worked on the project as a research fellow at the Flatiron Institute's Center for Computational Quantum Physics in New York City. "I've been working on these theory ideas for over five years, and seeing them come actually to be realized in experiments is exciting."
[...] The workhorses of the team's quantum computer are 10 atomic ions of an element called ytterbium. Each ion is individually held and controlled by electric fields produced by an ion trap, and can be manipulated or measured using laser pulses.
Each of those atomic ions serves as what scientists dub a quantum bit, or 'qubit.' Whereas traditional computers quantify information in bits (each representing a 0 or a 1), the qubits used by quantum computers leverage the strangeness of quantum mechanics to store even more information. Just as Schrödinger's cat is both dead and alive in its box, a qubit can be a 0, a 1 or a mashup — or 'superposition' — of both. That extra information density and the way qubits interact with one another promise to allow quantum computers to tackle computational problems far beyond the reach of conventional computers.
There's a big problem, though: Just as peeking in Schrödinger's box seals the cat's fate, so does interacting with a qubit. And that interaction doesn't even have to be deliberate. "Even if you keep all the atoms under tight control, they can lose their quantumness by talking to their environment, heating up or interacting with things in ways you didn't plan," Dumitrescu says. "In practice, experimental devices have many sources of error that can degrade coherence after just a few laser pulses."
The challenge, therefore, is to make qubits more robust. To do that, physicists can use 'symmetries,' essentially properties that hold up to change. (A snowflake, for instance, has rotational symmetry because it looks the same when rotated by 60 degrees.) One method is adding time symmetry by blasting the atoms with rhythmic laser pulses. This approach helps, but Dumitrescu and his collaborators wondered if they could go further. So instead of just one time symmetry, they aimed to add two by using ordered but non-repeating laser pulses.
Journal Reference:
Dumitrescu, Philipp T., Bohnet, Justin G., Gaebler, John P., et al. Dynamical topological phase realized in a trapped-ion quantum simulator, Nature (DOI: 10.1038/s41586-022-04853-4)
(Score: 1, Insightful) by Anonymous Coward on Saturday July 23 2022, @09:17AM (1 child)
Can anyone tell me how quantum computing differs from magnetic resonance spectroscopy, apart from the names, concepts and utility?
(Score: 3, Informative) by maxwell demon on Saturday July 23 2022, @11:44AM
NMR spectroscopy has been used for quantum computing, though it doesn't scale well. Of course most of the time when you are doing NMR spectroscopy, you are not interested in doing computation, but in figuring out properties of the substance.
The difference is, of course, that quantum computing is a concept that can be implemented in several ways, of which NMR spectroscopy is just one, while NMR spectroscopy is a physical process that can be used for quantum computing, but also can be (and most commonly is) used for other purposes.
Sort of like the difference between electronic circuits and classical computing.
The Tao of math: The numbers you can count are not the real numbers.
(Score: 4, Insightful) by Common Joe on Saturday July 23 2022, @01:39PM (11 children)
I'm glad upstart submitted the article, but I have to admit this made no sense to me. I'm just a common Joe on the street and have limited knowledge of physics.
I did read the article, but it sound like something out of a movie:
Ouch. Headache.
So, if anyone actually understood what was being said, I am very interested in the idea of two dimensional time in layman's terms, and how it applied to the experiment which basically used everyday lasers from our "real world" to maintain quantum cohesion. (Whatever quantum cohesion is.)
(Score: 2) by hendrikboom on Saturday July 23 2022, @03:15PM (7 children)
I have studied some physics, and I too am somewhat clueless about the details in this article. Or should I say because of the lack of details?
(Score: 2) by hendrikboom on Saturday July 23 2022, @03:19PM (6 children)
It is quantum mechanical. Quantum mechanics is incomprehensible without the mathematics, and there's no mathematics in the article.
Maybe that why it doesn't make enough sense to be figured out.
(Score: 2) by captain normal on Saturday July 23 2022, @06:33PM (1 child)
"...there's no mathematics in the article."
Sure there is,the Fibonacci Sequence:
https://www.investopedia.com/terms/f/fibonaccilines.asp [investopedia.com]
The main problem as I see it is that the article is basically a summary of the Nature article which is locked behind a paywall.
"It is easier to fool someone than it is to convince them that they have been fooled" Mark Twain
(Score: 4, Informative) by maxwell demon on Saturday July 23 2022, @07:49PM
But with a simple web search you'll find the arXiv [arxiv.org] version.
The Tao of math: The numbers you can count are not the real numbers.
(Score: 0) by Anonymous Coward on Saturday July 23 2022, @08:45PM (3 children)
> Quantum mechanics is incomprehensible
Does that bother anybody? I mean, I can accept God is unfathomable and works in mysterious ways. But fucking physics?
(Score: 3, Insightful) by maxwell demon on Sunday July 24 2022, @06:08AM (2 children)
You changed the meaning with your selective quote. The post said (emphasis by me):
That's a very different statement. It means you can comprehend it, you just have to put in the work and learn the mathematics.
The Tao of math: The numbers you can count are not the real numbers.
(Score: 0) by Anonymous Coward on Sunday July 24 2022, @09:51PM (1 child)
Well actually I was misquoting to get onto a wider point. There are plenty of people proud of the incomprehensibility of QM. It starts there and spreads all the way across modern physics. Nobody understands it, ain't it great? Praise the Lord.
(Score: 2) by maxwell demon on Monday July 25 2022, @04:49AM
[citation needed]
The Tao of math: The numbers you can count are not the real numbers.
(Score: 3, Interesting) by maxwell demon on Saturday July 23 2022, @08:12PM (1 child)
I did a look into the actual paper, and while I don't understand everything (I didn't take much time trying to understand it, though), I'll try to explain the parts that I understood:
The “two-dimensional time” refers to the fact that the irregular pattern can somehow be obtained by taking a regular 2D pattern and projecting it into one dimension. Since the one-dimensional pattern is a temporal pattern, they refer to this 2D pattern as two-dimensional time.
This irregular pattern somehow produces topologically protected edge states (don't ask me how). Topologically protected states happen at the boundary between regions of different topology of the state space. Basically, imagine there's two states, and in one region the first state is always lower than the second, and in the other region the first state is always higher. Now the states always change continuously, therefore when moving from one region to the other, the two states have to cross somewhere. Local disturbances can change where they cross, but not if they cross. This crossing is then a topologically protected state. OK, actually it's a bit more complicated, but this is the basic idea.
The term is not “quantum cohesion” but quantum coherence. Basically quantum coherence means that the quantum state is preserved. Now those topologically protected edge states happen to be good for preserving quantum coherence.
The Tao of math: The numbers you can count are not the real numbers.
(Score: 2) by Common Joe on Saturday July 23 2022, @08:18PM
A lot of what you said made some sense. I won't pretend to fully understand, but it clicked a lot better than the article.
Thank you!
(Score: 2) by Fnord666 on Monday July 25 2022, @07:03PM
https://arstechnica.com/science/2022/07/no-sugarcoating-donut-math-yields-way-to-make-qubits-last-longer/ [arstechnica.com]