Qubit Count

There have been a lot of announcements recently regarding new chips or new simulators that contain a record number of qubits.   We thought it would be useful to our readers to compile all the information into one handy table that you can see below. Note that the data shown for the hardware items are for physical qubits without any error correction.

As we see more announcements in the coming months, you should remember that not all qubits are created equal.  A design that has qubits with long coherence times, high gate fidelities, and large connectivities may provide far better results than one that has many more qubits without these characteristics.  Please refer to our Qubit Quality page for some data that compares various quality measures for a few different implementations.

The table below was compiled from publicly available sources as of the date listed at the bottom of this page.   Please let us know at info@quantumcomputingreport.com if you see any corrections that are needed or new entries to add.

Company Type Technology Now Next Goal
Intel Gate Superconducting 49 TBD
Google Gate Superconducting 72 TBD
IBM Gate Superconducting 53 TBD
Rigetti Gate Superconducting 16 128
USTC (China) Gate Superconducting 10 20
IonQ Gate Ion Trap 11 79
IQOQI/Univ. Ulm/Univ. Innsbruck Gate Ion Trap 20 TBD
NSF STAQ Project Gate Ion Trap N/A ≥64
Intel Gate Spin 26 TBD
Silicon Quantum Computing Gate Spin N/A 10
CEA-Leti/INAC/Institut Néel Gate Spin N/A 100
Univ. of Wisconsin Gate Neutral Atoms 49 TBD
Harvard/MIT Quantum Simulator Rydberg Atoms 51 TBD
Univ. of Maryland / NIST Quantum Simulator Ion Trap 53 TBD
D-Wave Annealing Superconducting 2048 5000
iARPA QEO Research Program Annealing Superconducting N/A 100
NTT/Univ. of Tokyo/Japan NII Qtm Neural Network Photonic 2048 >20,000

Updated September 18, 2019

Pierpaolo Malinverni
@ 2:16 am

All these qubits you list in your qubits count page are physical qubits but, to make a useful computation, we would need an additional number of qubits for error correction.
The number of error correction qubits is estimated to be in the range of 10^3 – 10^4 per physical qubit, which makes a big difference.
I would like to propose that you make clear that the qubits you mention in your page are physical qubits, and that at present no one has yet been able to make one logical qubit, the thing we need for computation.

    @ 11:47 am

    Thanks. I have added a sentence indicating that the hardware items reflect physical qubits. However, I would not agree that error correction is a hard requirement for all quantum computations. There are algorithms being researched such as VQE (Variable Quantum Eigensolver) and QAOA (Quantum Approximate Optimization Algorithm) that may be able to provide useful results on small quantum computers without error correction. A new term has been coined by Professor John Preskill for this called NISQ (Noisy Intermediate-Scale Quantum).

      Nqaba Ndlwana
      @ 4:28 am

      Hello Doug

      Just an enthusiast layperson who found your site yesterday. Just a suggestion for the scoreboards but could they be ordered, either ascending or descending, in order to more quickly and easily get a vague comparison. Include all caveats necessary though, as you did in the explanation.

        @ 9:45 am

        There actually is an order to the listing. First, the list is organized by Type and then by Technology. Notice in the Type column that all the Gates are together, all the Annealers are together, and all the Software Simulators are together. And in the Technology column all the Superconducting implementations are together as well as the Classical implementations. The reason for this is that it would not be correct to compare something like a software simulator to an annealer to a gate level hardware implementation because they are so much different.

          Nqaba Ndlwana
          @ 12:45 am

          Oh, I see. Thanks for pointing that out, as a layperson I just jump straight to the big numbers.

@ 7:54 am

thank you for creating this handy overview. It would be nice to have references (maybe via footnotes or links) for the listed numbers.

    @ 9:55 am

    Thank-you for your comment. It is a good idea and we will try to implement this as time permits. We have written a news article on almost all of these implementations. However we have not yet cross-referenced the article as shown on the News page to this list. If you do want to find the news article, we have a search feature on the web site. You can use the Search box at the very left bottom of each page to find the reference.

Chris S
@ 1:25 pm

You may want to read this article by Phil Ball who explains that the number of qubits is only a piece of the puzzle.


    @ 11:40 am

    We certainly agree. That is why we included a paragraph in the introduction to this section that mentions in bold face “you should remember that not all qubits are created equal” and we also publish another page titled “Qubit Quality” that provides various quality and connectivity measures.

    Doug Finke
    Managing Editor

@ 8:28 pm

Hello Doug, I could really see the effort behind tabling this, much appreciate it and many thanks for the consolidated information.
Just one suggestion if at all makes sense – as each Type & Technology could influence different industries, can we add another column to clarify the kind of business cases & industry.

    @ 10:11 pm

    I think it is a little too early to know if a certain technology is better suited for a particular industry versus a different technology. Right now the focus is to show any sort of quantum advantage over classical computing for whatever problem the researchers can find. If you are interested in understanding what type of problems future quantum computers might be well suited for in general, I would refer you to the article titled “The Best Applications for Quantum Computing” in the Analysis section of this web site.

    Doug Finke
    Managing Editor

@ 12:23 pm

Hi Doug thanks for listing these. I have launched a venture fund in silicon valley focused on QC and your site is very helpful. Would enjoy connecting sometime.

    @ 2:22 pm

    Thanks Skip. Please let us know when you complete any QC investments. We would like to add them to our Venture Capital tables.

    Doug Finke
    Managing Editor

@ 10:16 pm

Does NTT really have a 2048 qubit quantum computer? I thought the Japanese government said it was not quantum.

    @ 12:18 pm

    Although there is some debate about how well this NTT Quantum Neural Net machine actual works, their documentation does state that they take advantage of the quantum phenomena of superposition and entanglement. (See https://qnncloud.com/QNN-Document.html). Even though this architecture is much different than the other ones listed in the table, we classify it as a quantum computer because it does utilize these two phenomena.

    Doug Finke
    Managing Editor

@ 12:04 pm

ANKH .1 and Xanadu need to be added to the lists


hardware -Photonic Quantum computing
software – Pennylane & Strawberry fields


Ankh is launching Anubis Cloud a Quantum virtual Machine service for Data science professionals with jupyter notebook integration and Tensorflow + keras. GPU Cloud services coming soon 🙂

    @ 6:27 pm

    Thank-you for your comment. We have added ANKH.1 to the listing on the Private/Startups page. Xanadu was already listed on that page and their software is now listed on the Tools page.

    Doug Finke
    Managing Editor

Andrew Adams
@ 12:47 pm

Do you have a list of historical data from the last 10 years on Qubit developments.
I’ve compiled a list but is incomplete.

Ww are mainly doing this to investigate if Moores Law applies to QC, and if there is any co-relation to Qubits.
It is not each to get a comparison as there is so many types at presenr.!.

    @ 2:45 pm

    There is a web site called http://www.qubitcounter.com that shows some data on historical qubit count milestones. I can’t completely vouch for its accuracy because it shows some recent announcements of designs that are not yet in production. But perhaps the data on that web site can still be helpful to you.

    Doug Finke
    Managing Editor

@ 11:54 am

I believe Rigetti 19Q in fact has 20 qubits, not 19 (as the name suggests)



    @ 12:49 pm

    You are correct that the original design was for 20 qubits. However, one qubit wasn’t working properly so Rigetti documented this as 19 qubits. This chip is being superseded by Rigetti’s new Aspen architecture which will shortly have versions with many more qubits.

    Doug Finke
    Managing Editor

@ 1:25 am

Hi there!
I do not see Xanadu in the list?

    @ 10:54 am

    First, Xanadu’s technology is based upon qumodes instead of qubits. The difference is that qumodes encode information as a continuous variable. And second, Xanadu has not released publicly any information on how many qumodes they have in each system. When they release this information, we will include it in this table.

    Doug Finke
    Managing Editor


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