Jonathan Oppenheim
@postquantum.bsky.social
Quantum mechanic with a lot of ontological baggage.
https://www.ucl.ac.uk/oppenheim/
https://www.ucl.ac.uk/oppenheim/
Great article on quadratic gravity, and why researchers are attracted to it (it's renormalisable). The pure gravity action of postquantum-classical gravity is the same us that of quadratic gravity but with a different interpretation, and it doesn't suffer from ghosts! arxiv.org/abs/2402.17844 ⚛️🧪
November 19, 2025 at 1:39 PM
Great article on quadratic gravity, and why researchers are attracted to it (it's renormalisable). The pure gravity action of postquantum-classical gravity is the same us that of quadratic gravity but with a different interpretation, and it doesn't suffer from ghosts! arxiv.org/abs/2402.17844 ⚛️🧪
The #QIP2026 list of accepted papers is out! qip2026.lu.lv/programme/ac... highlighting some of the important papers in quantum computing in the past year. This is a fantastic slice from a very rich landscape. Congratulations to the authors! ⚛️🧪
Accepted papers
qip2026.lu.lv
November 18, 2025 at 11:47 AM
The #QIP2026 list of accepted papers is out! qip2026.lu.lv/programme/ac... highlighting some of the important papers in quantum computing in the past year. This is a fantastic slice from a very rich landscape. Congratulations to the authors! ⚛️🧪
A recent @nature.com article claims that classical (unquantised) gravity produces entanglement. We show that their model does not produce entanglement. Even if the model produced entanglement, it would be mediated by the quantised matter interaction, and not gravity. scirate.com/arxiv/2511.0... 🧪⚛️
Classical gravity cannot mediate entanglement
In Nature, 646, 813 (2025), Aziz and Howl claim that classical (unquantised) gravity produces entanglement. We show that their model does not produce entanglement. Even if the model produced entanglem...
scirate.com
November 11, 2025 at 3:24 PM
A recent @nature.com article claims that classical (unquantised) gravity produces entanglement. We show that their model does not produce entanglement. Even if the model produced entanglement, it would be mediated by the quantised matter interaction, and not gravity. scirate.com/arxiv/2511.0... 🧪⚛️
We'll enjoy it while it lasts!
I crossed an interesting threshold yesterday, which I think many other mathematicians have been crossing recently as well. In the middle of trying to prove a result, I identified a statement that looked true and that would, if true, be useful to me. 1/3
October 31, 2025 at 7:59 PM
We'll enjoy it while it lasts!
Another day, another arxiv paper claiming that classical gravity can produce entanglement. Last week's Nature paper continues to cause confusion. But classical fields can't create entanglement *even if* they directly couple two masses. Comment added at superposer.substack.com/p/no-classic...
October 28, 2025 at 3:24 PM
Another day, another arxiv paper claiming that classical gravity can produce entanglement. Last week's Nature paper continues to cause confusion. But classical fields can't create entanglement *even if* they directly couple two masses. Comment added at superposer.substack.com/p/no-classic...
Reposted by Jonathan Oppenheim
As promised... No, classical spacetime can’t produce entanglement. I can create entanglement by turning a knob on a laser, but the knob isn't mediating entanglement. Is the knob "producing" the entanglement? This week's Nature paper is causing confusion! superposer.substack.com/p/no-classic... 🧪⚛️
No they do not. I'll try to write something up in the next few days....
October 24, 2025 at 9:29 AM
As promised... No, classical spacetime can’t produce entanglement. I can create entanglement by turning a knob on a laser, but the knob isn't mediating entanglement. Is the knob "producing" the entanglement? This week's Nature paper is causing confusion! superposer.substack.com/p/no-classic... 🧪⚛️
As promised... No, classical spacetime can’t produce entanglement. I can create entanglement by turning a knob on a laser, but the knob isn't mediating entanglement. Is the knob "producing" the entanglement? This week's Nature paper is causing confusion! superposer.substack.com/p/no-classic... 🧪⚛️
No they do not. I'll try to write something up in the next few days....
October 24, 2025 at 9:29 AM
As promised... No, classical spacetime can’t produce entanglement. I can create entanglement by turning a knob on a laser, but the knob isn't mediating entanglement. Is the knob "producing" the entanglement? This week's Nature paper is causing confusion! superposer.substack.com/p/no-classic... 🧪⚛️
No they do not. I'll try to write something up in the next few days....
October 23, 2025 at 4:36 PM
No they do not. I'll try to write something up in the next few days....
What if the measurement problem isn't about explaining how the classical world emerges from the quantum world...
...but about what happens when quantum systems interact with something that's already classical?
Turns out, the collapse postulate + Born rule emerge!
scirate.com/arxiv/2510.0...
🧪⚛️🧵1/5
...but about what happens when quantum systems interact with something that's already classical?
Turns out, the collapse postulate + Born rule emerge!
scirate.com/arxiv/2510.0...
🧪⚛️🧵1/5
A one-world interpretation of quantum mechanics
The measurement problem is the issue of explaining how the objective classical world emerges from a quantum one. Here we take a different approach. We assume that there is an objective classical syste...
scirate.com
October 13, 2025 at 7:49 AM
What if the measurement problem isn't about explaining how the classical world emerges from the quantum world...
...but about what happens when quantum systems interact with something that's already classical?
Turns out, the collapse postulate + Born rule emerge!
scirate.com/arxiv/2510.0...
🧪⚛️🧵1/5
...but about what happens when quantum systems interact with something that's already classical?
Turns out, the collapse postulate + Born rule emerge!
scirate.com/arxiv/2510.0...
🧪⚛️🧵1/5
Maite Arcos's PhD results are hitting the arxiv! A resource theory of gambling, and a paper on adversarial thermodynamics are out today. Gambling provides an operational way to quantify who has more information. And it can be extended into the quantum domain!🧵🧪⚛️ 1/
October 10, 2025 at 7:15 AM
Maite Arcos's PhD results are hitting the arxiv! A resource theory of gambling, and a paper on adversarial thermodynamics are out today. Gambling provides an operational way to quantify who has more information. And it can be extended into the quantum domain!🧵🧪⚛️ 1/
Reposted by Jonathan Oppenheim
6,100 neutral-atom qubits trapped in a grid by lasers @caltech.edu ... is a lot.
www.caltech.edu/about/news/c...
www.caltech.edu/about/news/c...
Caltech Team Sets Record with 6,100-Qubit Array
The neutral-atom platform shows promise for scaling up quantum computers.
www.caltech.edu
September 25, 2025 at 8:18 PM
6,100 neutral-atom qubits trapped in a grid by lasers @caltech.edu ... is a lot.
www.caltech.edu/about/news/c...
www.caltech.edu/about/news/c...
They sure take electromagnetism seriously in @quantumaephraim.bsky.social's lab!
September 25, 2025 at 5:35 PM
They sure take electromagnetism seriously in @quantumaephraim.bsky.social's lab!
Reposted by Jonathan Oppenheim
In a recent Substack post, FQxI's Jonathan Oppenheim discusses how far #LLMS have progressed. @postquantum.bsky.social says "their answers often look very convincing on the surface until you go through them more carefully".
DISCUSS: forums.fqxi.org/d/4283-how-g...
DISCUSS: forums.fqxi.org/d/4283-how-g...
September 3, 2025 at 3:01 PM
In a recent Substack post, FQxI's Jonathan Oppenheim discusses how far #LLMS have progressed. @postquantum.bsky.social says "their answers often look very convincing on the surface until you go through them more carefully".
DISCUSS: forums.fqxi.org/d/4283-how-g...
DISCUSS: forums.fqxi.org/d/4283-how-g...
The CERN whitepaper, on testing the quantum nature of gravity, has even more co-authors and is now available on the arxiv, scirate.com/arxiv/2509.0.... Check it out! 🧪⚛️
A Spin-Based Pathway to Testing the Quantum Nature of Gravity
A key open problem in physics is the correct way to combine gravity (described by general relativity) with everything else (described by quantum mechanics). This problem suggests that general relativi...
scirate.com
September 3, 2025 at 1:09 PM
The CERN whitepaper, on testing the quantum nature of gravity, has even more co-authors and is now available on the arxiv, scirate.com/arxiv/2509.0.... Check it out! 🧪⚛️
Reposted by Jonathan Oppenheim
There is one fundamental phenomenon that quantum physics can't explain: gravity
go.nature.com/45v70f1
go.nature.com/45v70f1
Is gravity quantum? Experiments could finally probe one of physics’ biggest questions
Physicists are developing laboratory tests to give insight into the true nature of gravity.
go.nature.com
August 13, 2025 at 12:26 PM
There is one fundamental phenomenon that quantum physics can't explain: gravity
go.nature.com/45v70f1
go.nature.com/45v70f1
I'm at the African Institute for Mathematical Science Ghana this week for a quantum hackathon. Which is apparently called a Quantathon! Excited to interact with great students and researchers from across Africa. Live feed at t.co/J8UzPKc6Vx & schedule at qtedu.aims.edu.gh. Public lecture on Friday.
July 8, 2025 at 12:26 PM
I'm at the African Institute for Mathematical Science Ghana this week for a quantum hackathon. Which is apparently called a Quantathon! Excited to interact with great students and researchers from across Africa. Live feed at t.co/J8UzPKc6Vx & schedule at qtedu.aims.edu.gh. Public lecture on Friday.
Reposted by Jonathan Oppenheim
FACT THREAD on New Interstellar Object #A11pl3Z
This story unfolded pretty fast yesterday for a few reasons. The object was discovered on July 1st UTC by the Asteroid Terrestrial-impact Last Alert System, or ATLAS team. A #NASA funded survey at the University of Hawaii. atlas.fallingstar.com 🔭🧪
This story unfolded pretty fast yesterday for a few reasons. The object was discovered on July 1st UTC by the Asteroid Terrestrial-impact Last Alert System, or ATLAS team. A #NASA funded survey at the University of Hawaii. atlas.fallingstar.com 🔭🧪
July 2, 2025 at 3:27 PM
FACT THREAD on New Interstellar Object #A11pl3Z
This story unfolded pretty fast yesterday for a few reasons. The object was discovered on July 1st UTC by the Asteroid Terrestrial-impact Last Alert System, or ATLAS team. A #NASA funded survey at the University of Hawaii. atlas.fallingstar.com 🔭🧪
This story unfolded pretty fast yesterday for a few reasons. The object was discovered on July 1st UTC by the Asteroid Terrestrial-impact Last Alert System, or ATLAS team. A #NASA funded survey at the University of Hawaii. atlas.fallingstar.com 🔭🧪
Reposted by Jonathan Oppenheim
!!!!! Waking up to the news that we might have found an interstellar object passing through our Solar System - only the third ever seen. Looks convincing based on the orbit.
For any asteroid observers who have not heard about it already:
Newly-discovered #A11pl3Z is a candidate interstellar object.
cneos.jpl.nasa.gov/scout/#/obje...
Newly-discovered #A11pl3Z is a candidate interstellar object.
cneos.jpl.nasa.gov/scout/#/obje...
Scout: NEOCP Hazard Assessment
NASA's Near-Earth Object (NEO) web-site. Data related to Earth impact risk, close-approaches, and much more.
cneos.jpl.nasa.gov
July 2, 2025 at 7:08 AM
!!!!! Waking up to the news that we might have found an interstellar object passing through our Solar System - only the third ever seen. Looks convincing based on the orbit.
Reposted by Jonathan Oppenheim
NEW: NSF will be kicked out of their building. Announcement will be made tomorrow by HUD Sec. and Governor of VA. HUD will take over the NSF building over the next two years.
NSF staffer: "There is no planning for NSF, no identified future location, appropriation for a new building or a move."
NSF staffer: "There is no planning for NSF, no identified future location, appropriation for a new building or a move."
June 24, 2025 at 10:20 PM
NEW: NSF will be kicked out of their building. Announcement will be made tomorrow by HUD Sec. and Governor of VA. HUD will take over the NSF building over the next two years.
NSF staffer: "There is no planning for NSF, no identified future location, appropriation for a new building or a move."
NSF staffer: "There is no planning for NSF, no identified future location, appropriation for a new building or a move."
Reposted by Jonathan Oppenheim
Just click on this: skyviewer.app/explorer #RubinTelescope
Explorer | Skyviewer
skyviewer.app
June 24, 2025 at 2:58 PM
Just click on this: skyviewer.app/explorer #RubinTelescope
Sad news, Ray was both a a really kind man and a great scientist.
RIP Ray Laflamme, gone too soon.
Ray was a stellar scientist, the founding director of the IQC and of CIFAR's Quantum Information program, but more importantly a warm & generous human who built community and helped many (particularly junior researchers).
May his memory be a blessing.
Ray was a stellar scientist, the founding director of the IQC and of CIFAR's Quantum Information program, but more importantly a warm & generous human who built community and helped many (particularly junior researchers).
May his memory be a blessing.
June 21, 2025 at 5:51 PM
Sad news, Ray was both a a really kind man and a great scientist.
Reposted by Jonathan Oppenheim
What if gravity isn’t a pull from mass, but a push from entropy? @georgemusser.com reports on the latest version of an old idea.
www.quantamagazine.org/is-gravity-j...
www.quantamagazine.org/is-gravity-j...
June 13, 2025 at 1:59 PM
What if gravity isn’t a pull from mass, but a push from entropy? @georgemusser.com reports on the latest version of an old idea.
www.quantamagazine.org/is-gravity-j...
www.quantamagazine.org/is-gravity-j...
Is there a way to stem the endless cavalcade of cats, birds, and sunsets flooding my feed? No matter how many times I hit 'show less like this,' they keep coming. Anyone else drowning in cats? @rose.bsky.team @jay.bsky.team @support.bsky.team
June 13, 2025 at 1:32 PM
Is there a way to stem the endless cavalcade of cats, birds, and sunsets flooding my feed? No matter how many times I hit 'show less like this,' they keep coming. Anyone else drowning in cats? @rose.bsky.team @jay.bsky.team @support.bsky.team
Reposted by Jonathan Oppenheim
Scientists for Palestine is holding a school on quantum physics Palestinian students in Jordan in July, but they need donations to make it happen! 🇵🇸
www.scientists4palestine.org/palestinian-...
www.gofundme.com/f/support-pa...
www.scientists4palestine.org/palestinian-...
www.gofundme.com/f/support-pa...
Palestinian Advanced Physics School 2025 - Scientists For Palestine
The Palestinian Advanced Physics School 2025 (PAPS) will be held in-person at the University of Jordan between 26th — 31st July 2025. Additional students will join remotely from Gaza. The school is ai...
www.scientists4palestine.org
June 11, 2025 at 6:30 PM
Scientists for Palestine is holding a school on quantum physics Palestinian students in Jordan in July, but they need donations to make it happen! 🇵🇸
www.scientists4palestine.org/palestinian-...
www.gofundme.com/f/support-pa...
www.scientists4palestine.org/palestinian-...
www.gofundme.com/f/support-pa...
On Sunday, I'll be at the Cheltenham Science Festival, with Andrew Pontzen, Hiranya Peiris and Cham Ghag, discussing whether the phenomena we attribute to dark matter, could be explained by stochastic fluctuations in spacetime. Come say hello! www.cheltenhamfestivals.org/events/quant... 🧪⚛️
Quantum Dark Matter | Cheltenham Festivals
Astronomers have been amassing evidence for “dark matter” in space – far more mass than can be seen directly. Yet, despite intensive efforts, there is no
www.cheltenhamfestivals.org
June 6, 2025 at 12:34 PM
On Sunday, I'll be at the Cheltenham Science Festival, with Andrew Pontzen, Hiranya Peiris and Cham Ghag, discussing whether the phenomena we attribute to dark matter, could be explained by stochastic fluctuations in spacetime. Come say hello! www.cheltenhamfestivals.org/events/quant... 🧪⚛️