It is hard to beat the list present at Quantum computing report: quantumcomputingreport.com/players/.
The much less-complete Wikipedia page is also of interest: en.wikipedia.org/wiki/List_of_companies_involved_in_quantum_computing_or_communication It has the merit of having a few extra columns compared to Quantum computing report.
- Paulo Nussenzveig physics researcher at University of São Paulo. Laboratory page: portal.if.usp.br/lmcal/pt-br/node/323: LMCAL, laboratory of coherent manipulation of atoms and light. Google Scholar: scholar.google.com/citations?user=FbGL0BEAAAAJ
- Brazil Quantum: interest group created by students. Might be a software consultancy: www.terra.com.br/noticias/tecnologia/inovacao/pesquisadores-paulistas-tentam-colocar-brasil-no-mapa-da-computacao-quantica,2efe660fbae16bc8901b1d00d139c8d2sz31cgc9.html
- DOBSLIT dobslit.com/en/the-company/ company in São Carlos, as of 2022 a quantum software consultancy with 3 people: www.linkedin.com/search/results/people/?currentCompany=%5B%2272433615%22%5D&origin=COMPANY_PAGE_CANNED_SEARCH&sid=TAj two of them from the Federal University of São Carlos
- computacaoquanticabrasil.com/ Website half broken as of 2022. Mentions a certain Lagrange Foundation, but their website is down.
- QuInTec academic interest group
- www.terra.com.br/noticias/tecnologia/inovacao/pesquisadores-paulistas-tentam-colocar-brasil-no-mapa-da-computacao-quantica,2efe660fbae16bc8901b1d00d139c8d2sz31cgc9.html mentions 6 professors, 3 from USP 3 from UNICAMP interest group:
- drive.google.com/file/d/1geGaRuCpRHeuLH2MLnLoxEJ1iOz4gNa9/view white paper gives all names
- Celso Villas-Bôas
- Frederico Brito
- Gustavo Wiederhecker
- Marcelo Terra Cunha
- Paulo Nussenzveig
- Philippe Courteille
- sites.google.com/unicamp.br/quintec/home their website.
- a 2021 symposium they organized: www.saocarlos.usp.br/dia-09-quintec-quantum-engineering-workshop/ some people of interest:
- Samuraí Brito www.linkedin.com/in/samuraí-brito-4a57a847/ at Itaú Unibanco, a Brazilian bank
- www.linkedin.com/in/dario-sassi-thober-5ba2923/ from wvblabs.com.br/
- www.linkedin.com/in/roberto-panepucci-phd from en.wikipedia.org/wiki/Centro_de_Pesquisas_Renato_Archer in Campinas
- Quanby quantum software in Florianópolis, founder Eduardo Duzzioni
- thequantumhubs.com/category/quantum-brazil-news/ good links
- qubit.lncc.br/?lang=en Quantum Computing Group of the National Laboratory for Scientific Computing: pt.wikipedia.org/wiki/Laboratório_Nacional_de_Computação_Científica in Rio. The principal researcher seems to be www.lncc.br/~portugal/. He knows what GitHub is: github.com/programaquantica/tutoriais, PDF without .tex though.
- quantum-latino.com/ conference. E.g. 2022: www.canva.com/design/DAFErjU3Wvk/2xo25nEuqv9O7RbCPLNEkw/view
One of their learning sites: www.qutube.nl/
The educational/outreach branch of QuTech.
Not a quantum computing pure-play, they also do sensing.
Really weird and obscure company, good coverage: thequantuminsider.com/2020/02/06/quantum-computing-incorporated-the-first-publicly-traded-quantum-computing-stock/
Publicly traded in 2007, but only pivoted to quantum computing much later.
Quantum computers as experiments that are hard to predict outcomes by 
Ciro Santilli 40 Updated 2025-07-16
Ciro Santilli 40 Updated 2025-07-16One possibly interesting and possibly obvious point of view, is that a quantum computer is an experimental device that executes a quantum probabilistic experiment for which the probabilities cannot be calculated theoretically efficiently by a nuclear weapon.
This is how quantum computing was originally theorized by the likes of Richard Feynman: they noticed that "Hey, here's a well formulated quantum mechanics problem, which I know the algorithm to solve (calculate the probability of outcomes), but it would take exponential time on the problem size".
The converse is then of course that if you were able to encode useful problems in such an experiment, then you have a computer that allows for exponential speedups.
This can be seen very directly by studying one specific quantum computer implementation. E.g. if you take the simplest to understand one, photonic quantum computer, you can make systems for which you need exponential time to calculate the probabilities that photons will exit through certain holes and not others.
The obvious aspect of this idea is by coming from quantum logic gates are needed because you can't compute the matrix explicitly as it grows exponentially: knowing the full explicit matrix is impossible in practice, and knowing the matrix is equivalent to knowing the probabilities of every outcome.
Quantum computing is hard because we want long coherence but fast control by Ciro Santilli 40 Updated 2025-07-16
Ciro Santilli 40 Updated 2025-07-16Mentioned e.g. at:
These are two conflicting constraints:
- long coherence times: require isolation from external world, otherwise observation destroys quantum state
- fast control and readout: require coupling with external world
Pinned article: Introduction to the OurBigBook Project
Welcome to the OurBigBook Project! Our goal is to create the perfect publishing platform for STEM subjects, and get university-level students to write the best free STEM tutorials ever.
Everyone is welcome to create an account and play with the site: ourbigbook.com/go/register. We belive that students themselves can write amazing tutorials, but teachers are welcome too. You can write about anything you want, it doesn't have to be STEM or even educational. Silly test content is very welcome and you won't be penalized in any way. Just keep it legal!
Intro to OurBigBook
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This feature makes it possible for readers to find better explanations of any topic created by other writers. And it allows writers to create an explanation in a place that readers might actually find it.
Figure 1. Screenshot of the "Derivative" topic page. View it live at: ourbigbook.com/go/topic/derivativeVideo 2. OurBigBook Web topics demo. Source. - local editing: you can store all your personal knowledge base content locally in a plaintext markup format that can be edited locally and published either:This way you can be sure that even if OurBigBook.com were to go down one day (which we have no plans to do as it is quite cheap to host!), your content will still be perfectly readable as a static site.
- to OurBigBook.com to get awesome multi-user features like topics and likes
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Figure 3. Visual Studio Code extension installation.
Figure 4. Visual Studio Code extension tree navigation.
Figure 5. Web editor. You can also edit articles on the Web editor without installing anything locally.Video 3. Edit locally and publish demo. Source. This shows editing OurBigBook Markup and publishing it using the Visual Studio Code extension.Video 4. OurBigBook Visual Studio Code extension editing and navigation demo. Source. 
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All our software is open source and hosted at: github.com/ourbigbook/ourbigbook
Further documentation can be found at: docs.ourbigbook.com
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