Quantum computers could revolutionize the way we tackle problems that stump even the best classical computers.
Single atom transistor recently introduced has been seen as a tool that could lead the way to building a quantum computer. For general introduction how quantum computer work, read A tale of two qubits: how quantum computers work article.
D-Wave Announces Commercially Available Quantum Computer article tells that computing company D-Wave has announced that they’re selling a quantum computing system commercially, which they’re calling the D-Wave One. D-Wave system comes equipped with a 128-qubit processor that’s designed to perform discrete optimization operations. The processor uses quantum annealing to perform these operations.
D-Wave is advertisting a number of different applications for its quantum computing system, primarily in the field of artificial intelligence. According to the company, its system can handle virtually any AI application that can be translated to a Markov random field.
Learning to program the D-Wave One blog article tells that the processor in the D-Wave One – codenamed Rainier – is designed to perform a single mathematical operation called discrete optimization. It is a special purpose processor. When writing applications the D-Wave One is used only for the steps in your task that involve solving optimization problems. All the other parts of your code still run on your conventional systems of choice. Rainier solves optimization problems using quantum annealing (QA), which is a class of problem solving approaches that use quantum effects to help get better solutions, faster. Learning to program the D-Wave One is the first in a series of blog posts describing the algorithms we have run on D-Wave quantum computers, and how to use these to build interesting applications.
But is this the start of the quantum computers era? Maybe not. D-Wave Announces Commercially Available Quantum Computer article comments tell a story that this computer might not be the quantum computer you might be waiting for. It seem that the name “quantum computer” is a bit misleading for this product. There are serious controversies around the working and “quantumness” of the machine. D-Wave has been heavily criticized by some scientists in the quantum computing field. First sale for quantum computing article tells that uncertainty persists around how the impressive black monolith known as D-Wave One actually works. Computer scientists have long questioned whether D-Wave’s systems truly exploit quantum physics on their products.
Slashdot article D-Wave Announces Commercially Available Quantum Computer comments tell that this has the same central problem as before. D-Wave’s computers haven’t demonstrated that their commercial bits are entangled. There’s no way to really distinguish what they are doing from essentially classical simulated annealing. Recommended reading that is skeptical of D-Wave’s claims is much of what Scott Aaronson has wrote about them. See for example http://www.scottaaronson.com/blog/?p=639, http://www.scottaaronson.com/blog/?p=198 although interestingly after he visited D-Wave’s labs in person his views changed slightly and became slightly more sympathetic to them http://www.scottaaronson.com/blog/?p=954.
So it is hard to say if the “128 qubits” part is snake oil or for real. If the 128 “qubits” aren’t entangled at all, which means it is useless for any of the quantum algorithms that one generally thinks of. It seem that this device simply has 128 separate “qubits” that are queried individually, and is, essentially an augmented classical computer that gains a few minor advantages in some very specific algorithms (i.e. the quantum annealing algorithm) due to this qubit querying, but is otherwise indistinguishable from a really expensive classical computer for any other purpose. This has the same central problem as before: D-Wave’s computers haven’t demonstrated that their commercial bits are entangled.
Rather than constantly adding more qubits and issuing more hard-to-evaluate announcements, while leaving the scientific characterization of its devices in a state of limbo, why doesn’t D-Wave just focus all its efforts on demonstrating entanglement, or otherwise getting stronger evidence for a quantum role in the apparent speedup? There’s a reason why academic quantum computing groups focus on pushing down decoherence and demonstrating entanglement in 2, 3, or 4 qubits: because that way, at least you know that the qubits are qubits! Suppose D-Wave were marketing a classical, special-purpose, $10-million computer designed to perform simulated annealing, for 90-bit Ising spin glass problems with a certain fixed topology, somewhat better than an off-the-shelf computing cluster. Would there be even 5% of the public interest that there is now?
1,114 Comments
Tomi Engdahl says:
Kahden kubitin portti FINfet-transistorissa
https://www.nanobitteja.fi/uutiset.html?236364
Tomi Engdahl says:
Baselin yliopiston ja NCCR SPIN:n tutkijat ovat saavuttaneet ensimmäisen ohjattavan vuorovaikutuksen kahden aukko-spin -kubitin välillä tavanomaisessa piitransistorissa. Universaali kvanttilaskenta vaatii sekä yhden kubitin ohjauksen että kahden kubitin vuorovaikutuksia.
Saavutettu läpimurto avaa mahdollisuuden integroida miljoonia tällaisia kubitteja yhdelle sirulle nykyisiä valmistusprosesseja käyttäen.
Nämä tutkijat luottavat kubittityyppiin, joka käyttää elektronin tai aukon spiniä (sisäistä kulmamomenttia). Sekä aukoilla että elektroneilla on spin, joka voi ottaa yhden kahdesta tilasta: ylös tai alas. Elektronin spiniin verrattuna aukon spinin etuna on, että sitä voidaan ohjata kokonaan sähköisesti ilman, että sirulle tarvitaan lisäkomponentteja, kuten mikromagneetteja.
https://www.nanobitteja.fi/uutiset.html?236364
Tomi Engdahl says:
Pseudomagic quantum states: A path to quantum supremacy
https://phys.org/news/2024-06-pseudomagic-quantum-states-path-supremacy.html
A new study in Physical Review Letters (PRL) introduces the concept of pseudomagic quantum states, which appear to have high stabilizerness (or complexity) and can move us closer to achieving quantum supremacy.
Tomi Engdahl says:
Physicists confirm quantum entanglement persists between top quarks, the heaviest known fundamental particles
https://phys.org/news/2024-06-physicists-quantum-entanglement-persists-quarks.html
Tomi Engdahl says:
https://www.uusiteknologia.fi/2024/06/18/kilpailutus-isommasta-kvanttikoneesta/
VTT vauhdittaa kilpailutuksella seuraavan kvanttitietokoneeseen hankintaa. Samalla selvitetään kvanttikoneen mahdollisuuksia erikoistua materiaalien suunnitteluun ja kehittämiseen. Tulossa on 300 kubitin kvanttitietokone esimerkiksi materiaalitutkimukseen.
Tomi Engdahl says:
Quantum computers are like kaleidoscopes: Why unusual metaphors help illustrate science and technology
https://phys.org/news/2024-06-quantum-kaleidoscopes-unusual-metaphors-science.html
Tomi Engdahl says:
https://studyfinds.org/quantum-computing-breakthrough/
Tomi Engdahl says:
Kvanttidataa lähettiin kuidussa ensimmäistä kertaa
https://etn.fi/index.php/13-news/16358-kvanttidataa-laehettiin-kuidussa-ensimmaeistae-kertaa
Kvanttitietokoneiden kehittyessä yksi tutkimuksen aiheita on se, miten kvanttikoneiden dataa voisi lähettää internetissä. Tällä hetkellä kvanttitieto on epävakaata, pitkien etäisyyksien päässä ja kvanttibitit eli kubitit katoavat helposti tai pirstoutuvat lähetyksen aikana.
Klassisia bittejä lähetetään nykyään valopulsseina kuituoptisten kaapeleiden yli. Signaaleja vahvistetaan toistimilla matkan varrella. Jotta kubitteja voisi lähettää samalla tavoin, tarvitaan laitteita, verkon yli riippumatta siitä, kuinka pitkälle datan on kuljettava.
Tällaisia laitteita on tutkittu Lontoon Imperial Collegessa, Southamptonin yliopistossa sekä Stuttgartin ja Wurzburgin yliopistoissa Saksassa. Tutkijat väittävät nyt lähettäneensä kubitteja ensimmäistä kertaa tavallisten valokuitukaapeleiden yli. Tulokset on julkaistu Scientific Advances -lehdessä.
Tomi Engdahl says:
Why every quantum computer will need a powerful classical computer
Error-correcting a quantum computer can mean processing 100TB every second.
https://arstechnica.com/science/2024/07/why-every-quantum-computer-will-need-a-powerful-classical-computer/
Error detection vs. the data
All qubits are fragile, tending to lose their state during operations, or simply over time. No matter what the technology—cold atoms, superconducting transmons, whatever—these error rates put a hard limit on the amount of computation that can be done before an error is inevitable. That rules out doing almost every useful computation operating directly on existing hardware qubits.
The generally accepted solution to this is to work with what are called logical qubits. These involve linking multiple hardware qubits together and spreading the quantum information among them. Additional hardware qubits are linked in so that they can be measured to monitor errors affecting the data, allowing them to be corrected. It can take dozens of hardware qubits to make a single logical qubit, meaning even the largest existing systems can only support about 50 robust logical qubits.
Riverlane’s founder and CEO, Steve Brierley, told Ars that error correction doesn’t only stress the qubit hardware; it stresses the classical portion of the system as well. Each of the measurements of the qubits used for monitoring the system needs to be processed to detect and interpret any errors. We’ll need roughly 100 logical qubits to do some of the simplest interesting calculations, meaning monitoring thousands of hardware qubits. Doing more sophisticated calculations may mean thousands of logical qubits.
That error-correction data (termed syndrome data in the field) needs to be read between each operation, which makes for a lot of data. “At scale, we’re talking a hundred terabytes per second,” said Brierley. “At a million physical qubits, we’ll be processing about a hundred terabytes per second, which is Netflix global streaming.”
Tomi Engdahl says:
Multiple governments around the world have secretly agreed to restrict the export of quantum computers
News
By Nick Evanson published 8 July 2024
The move has stumped the scientific community as there’s no obvious reason for it.
https://www.pcgamer.com/hardware/multiple-governments-around-the-world-have-secretly-agreed-to-restrict-the-export-of-quantum-computers/
Tomi Engdahl says:
Using artificial intelligence to make quantum computers a reality
https://www.earth.com/news/using-artificial-intelligence-ai-to-make-quantum-computers-reality/
Have you ever considered the potential of artificial intelligence (AI) to unlock the secrets of advanced quantum computing?
This once seemingly impossible feat may soon become a reality, as suggested by new research from Australia’s national science agency, CSIRO.
AI and quantum computing noise
The research, published in the prestigious Physical Review Research journal, presents a fascinating and important concept.
It indicates AI’s remarkable potential to process and resolve quantum errors, which are famously termed as ‘qubit noise’.
Now, why do these quantum errors matter so much in the universe of quantum computing?
This noise, which arises from various sources such as environmental interference and imperfections in the quantum system, apparently is the largest hurdle in transitioning quantum computers from being purely experimental devices to practical, everyday tools.
Tomi Engdahl says:
Scientists beat supercomputers with quantum tech that simulates electron motion
Researchers have successfully simulated the complex behavior of electrons in a solid-state material using a quantum computer.
https://interestingengineering.com/science/china-quantum-device-simulating-electrons
Tomi Engdahl says:
New quantum computer smashes ‘quantum supremacy’ record by a factor of 100 — and it consumes 30,000 times less power
News
By Keumars Afifi-Sabet published July 11, 2024
The 56-qubit H2-1 computer has broken the previous record in the ‘quantum supremacy’ benchmark first set by Google in 2019.
https://www.livescience.com/technology/computing/new-quantum-computer-smashes-quantum-supremacy-record-by-a-factor-of-100-and-it-consumes-30000-times-less-power