[HN Gopher] Quantum dynamics on your laptop? New technique moves...
       ___________________________________________________________________
        
       Quantum dynamics on your laptop? New technique moves us closer
        
       Author : ceolin
       Score  : 60 points
       Date   : 2025-10-12 09:26 UTC (9 days ago)
        
 (HTM) web link (www.buffalo.edu)
 (TXT) w3m dump (www.buffalo.edu)
        
       | hershkumar wrote:
       | Reading their paper, it does seem like this method is
       | significantly simpler than using something like MPS, my main
       | concern is the practical coupling regime for which this method
       | works, I would imagine that it would fail closer to critical
       | points in theories with phase transitions?
        
         | nyeah wrote:
         | I'm curious, are any quantum simulators accessible to sort of
         | hobbyists?
         | 
         | I have a background in solid state physics from coursework, but
         | I've never really used QM for almost anything outside of
         | school.
        
           | krastanov wrote:
           | I think you will have best luck by searching for "open
           | quantum systems" toolboxes in your language of choice. My
           | preferences are, in order:
           | 
           | - QuantumOptics.jl in Julia
           | 
           | - QuantumToolbox.jl in Julia
           | 
           | - qutip in python
           | 
           | These are all "just" nice domain specific wrappers around
           | linear algebra and differential equation tools. They do the
           | "silly" exponentially expensive simulation technique that
           | works for any quantum system. If you are interested in
           | efficient (not exponential) simulation techniques that
           | support only a subset of all quantum dynamics try out:
           | 
           | - stabilizer formalism (e.g. for error correction) with
           | QuantumClifford.jl or stim
           | 
           | - Gaussian quantum optics (e.g. for laser physics) with
           | Gabs.jl
           | 
           | - tensor networks (e.g. for arbitrary low-rank entanglement)
           | with ITensors.jl
        
             | nyeah wrote:
             | Thanks a lot!
        
               | hershkumar wrote:
               | If you prefer python, tenpy is quite nice for tensor
               | networks as well.
        
               | nyeah wrote:
               | Thanks! I am kind of stuck in Python, or at least stuck
               | outside of Julia.
        
           | Bengalilol wrote:
           | Not perfectly answering your request, but did you look at
           | https://github.com/topics/quantum-computing?o=desc&s=updated
        
             | nyeah wrote:
             | I haven't, thanks.
        
           | the__alchemist wrote:
           | Try ORCA and GROMACS. Accessible as you can DL them and there
           | are lots of docs. But very high learning curve, and not
           | graphical on their own.
        
             | nyeah wrote:
             | Thanks a lot.
        
         | quantumtwist wrote:
         | This is a nice practical technique for open quantum systems
         | with relatively low entanglement. The introduction lays out
         | exactly what regime they're aiming at: 1. Affordable (laptop
         | scale) 2. Captures "sufficient" quantum effects (low
         | entanglement regime; you accurately can't simulate a quantum
         | computer with this) 3. Straightforward to implement. From a
         | cursory glance, it does all three. I'm slightly surprised that
         | TWA hasn't been applied to open systems extensively before, but
         | it was always a relatively obscure technique. I'm guessing this
         | should be quite useful in practice for e.g. AMO and cavity
         | systems with relatively large dissipation terms that prevent
         | entanglement build up. However, I'd guess this wouldn't do very
         | well near phase transitions. All-in-all, a nice new technique
         | for a regime that didn't have too many options.
        
           | hershkumar wrote:
           | Yeah this seems like a very useful technique for ground state
           | properties, I'm also surprised in retrospect, having never
           | heard of TWA before now.
        
         | andyferris wrote:
         | With _quantum_ phase transitions, yes.
        
       | the__alchemist wrote:
       | I'm very interested in this class of approximations on consumer
       | hardware from a different perspective: Simulating (simple)
       | biological systems and organic molecules. Background: I'm
       | building out the rust structural bio OSS ecosystem, and a GUI/3D
       | CAD-style visualizer. It has molecular dynamics integrated
       | tightly, and is designed to "just work" without fuss, setup, or
       | errors.
       | 
       | The problem: It is reliant on atom-centered partial charge, and
       | pre-calculated parameters for its Newtonian forces. These are
       | available for a set of 30k or so organic molecules, and most
       | protein, lipid, and nucleic acid configurations. The problems:
       | Making it work for arbitrary systems, and doing better than these
       | specifically-tuned models. I want the general case, and it to
       | work in a no-fuss way.
       | 
       | I am now looking into the TWA, and am interested in this class of
       | approximation in general. I have the UI and traditional MD system
       | mostly ready; getting ready to tackle this problem. This is a
       | much simpler setup than the ones physicists are interested, and
       | that the article covers, since we can focus on stable covalent-
       | bonded systems of atoms.
        
         | gilleain wrote:
         | That's Daedalus is it? Went to look up how your project is
         | doing, and had to go through github stars - might be worth
         | putting a link to it in your HN profile? Assuming you don't
         | mind making that link explicit :)
        
           | the__alchemist wrote:
           | Yep! it's a grind. Good call on the profile!
        
       ___________________________________________________________________
       (page generated 2025-10-21 23:01 UTC)