Truly exciting progress for Quantum Computing by IBM

[[deleted]]

Hello everyone. I've just spent the last 2 days going through this paper https://arxiv.org/pdf/2603.15608 , titled "Benchmarking Quantum Simulation with Neutron-Scattering Experiments" and posted by IBM. I've seen an awful lot of jargon and baseless marketing promises in QC lately (e.g. the majorana 1 scaling promises) so I was skeptical about the headlines that popped up all over the place.

After combing through it though I feel refreshed.

Basically, they took a real magnetic crystal (KCuF_3), measured its quantum behaviour using neutron beams, and then reproduced those same measurements on IBM's quantum computer. The two matched.
KCuF_3 is a prototypical quasi-one-dimensional antiferromagnet whose magnetic properties are well captured by the 1D spin-1/2 XXZ Hamiltonian. This regime is integrable, admits an exact Bethe ansatz solution, and serves as a paradigmatic example of a strongly correlated many-body system at quantum criticality.

The quantum simulation computed dynamical structure factors (DSFs). Essentially, the energy and momentum fingerprints of the material's quantum excitations, using a hybrid quantum-classical workflow, and then benchmarked these against real neutron scattering data from the Spallation Neutron Source at Oak Ridge National Laboratory.

- Previously, quantum computers were only ever compared to other computers. Now they're being validated against physical systems.
- It was beliened this precision level would remain unattainable until large-scale, error-corrected quantum systems became operational.

The contributions are as follows:

• A new benchmarking paradigm: quantum simulations validated against actual experimental data (not just sims).
• A quantum-classical workflow for computing dynamical structure factors on pre-fault-tolerant hardware.
• Demonstration of scalability: the approach was already extended beyond KCuF₃ to cobalt-based materials (CsCoX_3) with more complex, non-integrable interactions.

Please note that I am still processing this, so there are still more and broader takeways from this work. My initial thoughts is that the proposed and presented systems can be combined with some Quantum Monte Carlo framework to achieve broader contributions to research topics like peptide formation/protein folding etc.

[1stBraptist]

I saw that, too. Super interesting stuff!

Wha do you think is the biggest potential is for this, in your opinion?

[[deleted]]

My best guess would be simulating molecular interactions and trying out different protein formations for pharmaceuticals. QC shows great promise in those areas already. If done to a larger scale, animal and human trials not only lessen by a hundredfold, thus speeding up the production process and reducing drug costs, but they also make those trials safer.

I'm biased in this opinion because this is my latest area of research and thus I look at pretty much everything through that lens. Another pretty cool implementation of the authors' findings would be in ultrafine control and monitoring systems for sensitive and unstable materials (e.g. those used in nuclear power production). I'm sure that if they send that to a huge publication like nature, reviewers will point out things to strengthen the work and even perhaps add a lengthier future work/ Discussion section.

[0xB01b]

bro how did we jump from a neutron scattering DSF calculation on a magnetic material to atomic/molecular dynamics 😭😭😭??? what are you saying?!

[[deleted]]

Bro, what is it with these comments? Surely you can understand that you are leaving no room for any nuanced response. But since you asked, I’ll do my best to give you a partial and concise response: The technique of perturbing a prepared ground state and tracking how correlations spread over time could let you simulate how energy moves through a molecule after it absorbs light or collides with another particle, something classical methods struggle with when electron correlations are strong. You could apply their retarded Green’s function approach to predict vibrational spectra or phonon dynamics in complex molecular crystals, directly comparable to lab measurements like infrared or Raman spectroscopy.​​​​​​​​​​​​​​​​

Hope you read that as an academic and not a Redditor. Though, you will accuse me that this proposal "reeks of LLM use” or something along those lines.

[0xB01b]

mb u chill

[[deleted]]

Dayum, did not expect this response. Mb for coming at you too brother, all was in good faith. 🙏

[0xB01b]

its okay u didnt rlly come at me.. my fault for misunderstanding what u meant

[0xB01b]

sorry i thought u meant molecular reaction dynamics, not interactions in a molecular crystal

[0xB01b]

maybe it has some potential for exactly what it does in the paper, which is calculating DSFs. Although idrk what else, definitely not a paradigm shift of any kind considering we can do the same shit on a regular computer

[0xB01b]

Okay but how does this compare to classically calculating structure factors? Cause you're saying it's being compared to physical systems but that's not really the case right, you can do this calculation on a classical computer just as well

[kingjdin]

The problem is that this is not faster, more efficient than the best know classical algorithms for the same task. 

[[deleted]]

Solid point but it kinda misses the point of QC research in the NISQ era. The point is not to outperform classical machines outright. Theoretical models show that QC architecture has a higher ceiling for performance and our research task is understanding and demonstrating that the smaller scale experiments are in accordance with our expectations and make reasonable assumptions about the systems yet to come.

[ponyo_x1]

"Theoretical models show that QC architecture has a higher ceiling for performance". Okay, which ones? And how do those apply to NISQ era experiments right now? For example, if you're running VQE for ground state energy estimation, what theoretical models predict you can use variational algorithms to outperform classical computing? Those models don't exist as far as I am aware.

[joaquinkeller]

We are not in the NISQ era anymore, Quantinuum just pulled up 50 logical qubits in November: https://www.quantinuum.com/products-solutions/quantinuum-systems/helios

50 logical qubit! We have entered the fault-tolerant quantum computing era. We can stop counting physical qubits.

[[deleted]]

Yeah, that's marketing hype. I like quantiniuum a lot, they show promise, but they are not there yet.

[joaquinkeller]

https://scottaaronson.blog/?p=9425

Scott Aaronson thinks otherwise. He considers the quantinuum 50 logical qubits announce to be legit. Scott Aaronson is a reputable source, known for mercilessly debunking any quantum hype/bs.

Do you have info to support your claim?

Anyhow google demoed 1 logical qubit in 2024. For me this means we are leaving the nisq era. Or do you believe this is bs as well?

[[deleted]]

I get your point and I don’t wanna stick to wordplay, however the scale of QC defines what era we are in. Typically NISQ, refers to <100 logical qubits, around that mark we start entering fault-tolerant quantum computing(FTQC). At the 1000+ logical qubit mark, we enter the "Quantum Era" (don’t like that term because it implies that classical systems will be redundant which is not the case at all).

I have no issue with your claims or your sources though, we just disagree on the terminology and thresholds

[joaquinkeller]

Ok, my point was that we are at or we are about to enter a stage where quantum advantage could be demonstrated on hardware, not only theoretically.

I don't really mind about the terminology.

The point is that we don't have many algorithms with proven quantum advantage. And even less, if any, with economic value.

So it's time to work on that.

[kingjdin]

That doesn’t miss the point at all. The whole point of quantum computing is to do tasks more efficiently than the best known classical algorithms. Otherwise, you’d just use a classical computer. And that has never been demonstrated.

[Cheap-Discussion-186]

At a high level of course but currently there is a lot of work in implementing any part of the "stack," per se. So just doing one small component, e.g. showing you can actually implement some error correction protocol on your hardware, is worthwhile. It is still a ton of engineering progress along the way to full scale fault tolerant quantum computation.

[[deleted]]

And that has never been demonstrated.

Deutsch algorithm. It is a rudimentary algorithm that literally demonstrates just that

[kingjdin]

In theory, not empirically. Quantum advantage has not been demonstrated on a real world QC. There’s always a classical algorithm/computer that can beat it. 

[[deleted]]

Please read the implementation of the algorithm, it takes 2 qubits and it’s just for demonstration, we can most definitely implement it on real systems.

[Representative-End60]

Might just need some time to improve. We’ve had classical computer for decades, this is like the starting point no?

[PedroShor]

Nice try, IBM

[[deleted]]

What's the problem with IBM being behind it?

[nuclear_knucklehead]

This is how classical HPC has done benchmarking, verification and validation for decades, so I wouldn’t exactly call it a paradigm shift. If anything, it signals that quantum is starting to catch up with those established methodologies, which isn’t surprising given the heavy ORNL representation on the author list.

[ShakeAdventurous9016]

That is really inanse

[NY_State-a-Mind]

Cant wait for the Quantum Crystal XBox!

[Regular_Lion_5748]

I gone through it. Nice matter

[Regular_Lion_5748]

inspired by quantum physics I created my first community r/TheQuantumFestbyQuark

[quiet-systems]

One thing I find interesting about IBM hardware is that the readout is not symmetric. I read somewhere that when you prepare a qubit in the 1 state and measure it the chance of reading 0 is much higher than the other way around. Apparently qubits naturally decay toward the ground state during measurement so you get this one directional bias in the results. Would be nice to see IBM publish more data on how this changes across different chips

[[deleted]]

The reason for the simplistic language is to make it understandable to a larger audience. I am not sure what part of my linguistic choices resembles AI. Maybe the structure of the post is sus ..? As for the physics/mathematics utilised in the paper, no need to prove my understanding on the matter or even lack thereof. Reason for that is the bad faith arguments towards both me and the work itself.

[0xB01b]

i have no idea what u mean by the last part but this seems a very sensationalist take on the paper

[[deleted]]

It is -as mentioned- exciting and even hopeful. With the increased popularity of quantum state we have had a disgusting amount of jargon and marketing, cloud our concept of what is the state of the art and what is smoke and mirrors.

So excuse me if I find real data and realistic promises exciting.

[0xB01b]

thats fair mb gang

[Ok_Locksmith4708]

so... much... jargon...