Dr Jared Jeyaretnam ⚛️🧪
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jaredjeya.github.io
Dr Jared Jeyaretnam ⚛️🧪
@jaredjeya.github.io
790 followers 460 following 260 posts
I study non-equilibrium quantum many-body physics from a quantum circuit perspective at the University of Nottingham. Also passionate about science outreach! He/him

🌐 jaredjeya.github.io (still a WIP!)

PS: All opinions solely my own.
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jaredjeya.github.io
I’ve always thought the problem with quantum computers is that they don’t cost nearly enough money (ideally, at least a million dollars per kg!), and should experience heavy vibrations and crushing G-forces after being calibrated. ⚛️🧪
E*** M*** on X, The Everything App: “Quantum computing is best done in the permanently shadowed craters on the Moon” 107,000 idiots have liked this Xeet.
November 2, 2025 at 10:47 PM
jaredjeya.github.io
Just finished the final day of the Nottingham Workshop on Quantum Non-Equilibrium Dynamics!! Lots of great talks, and great discussions too 😄
A photo of one of the talks. People are sitting in chairs watching someone present a talk, specifically Mark Mitchison (KCL) on the topic of process tensors.
September 26, 2025 at 3:55 PM
jaredjeya.github.io
The British Isles, according to the New York Times.

(I think some of my old colleagues from Leeds might have an aneurysm if they see this!)
A screenshot from a New York Times article: "I have great sympathy for the police," said Paul Wragg, a professor of media law at the University of Leeds, north of London. He said that the public would likely be…” An outline map of the British Isles. London is labelled, and every other part is labelled relative to London: for example, Wales is “West of London”, Scotland is “far north of London”, and Ireland is “Far west of London”
September 10, 2025 at 7:43 PM
jaredjeya.github.io
Not your usual grafitti… ⚛️
A grey shutter, covered in white grafitti. In the middle someone has scrawled both the time-dependent and time-independent Schrödinger equations, as well as some other maths, in sharpie
August 7, 2025 at 2:27 PM
jaredjeya.github.io
Pros of showing up to an anti-cuts rally:

• Stand in solidarity with colleagues
• Protect your university from shredding its reputation
• Defend research and innovation
• This cute little dog who barked (loudly!) every time people clapped 🥰

#AcademicChatter
A small black and brown dog in the middle of barking, nestled between someone’s legs. There are some people standing around the white-tiled courtyard although you can’t see their faces. One of them is holding a purple and green Unison flag A wide angle shot of the same courtyard. Many people are standing around, waving flags and banners from different unions. In the background someone is giving a speech
July 21, 2025 at 11:39 AM
jaredjeya.github.io
Hey! I have a website now 👨🏻‍💻

jaredjeya.github.io

Still a WIP as I’m figuring out how it all works and what to put on it, though (I used a slightly over-engineered template 😅).

Also if anyone knows how to make images show up in the link card, that would be cool!
A screenshot of my new website, showing a little profile of me (with my picture) and a brief description. There is some text below this: “About me I am interested in non-equilibrium quantum many-body physics - in particular, ergodicity breaking (where matter taken out of equilibrium…” There is also a “hamburger” menu in the top right. (If you want to read more, visit the site!)
May 31, 2025 at 3:31 PM
jaredjeya.github.io
Ok here’s my attempt to come up with time travel in this scenario.

Let’s assume that the “shortcut” works in any reference frame (otherwise that breaks the equivalence principle).

Consider this spacetime diagram:
A spacetime diagram described in the next tweet
May 19, 2025 at 5:37 PM
jaredjeya.github.io
Poster session at QuSymDyn, Munich! Come speak to me if you want to know more about disorder-free localisation in the Schwinger model :)
A poster on “Hilbert space fragmentation at the origin of disorder-free localisation in the lattice Schwinger model”, showing a number of graphs, equations and diagrams
April 15, 2025 at 3:26 PM
jaredjeya.github.io
Happy pi(zza) day!

(Although I prefer to celebrate on 22/7 - it’s a lot more accurate 😉) #PiDay
A delicious chorizo & ham pizza, in a brown pizza box. It’s sitting on a dark wooden table in a pub. A half-drunk pint of stout is also visible!
March 14, 2025 at 7:54 PM
jaredjeya.github.io
Just sent this to their contact form! #AcademicChatter ⚛ 🧪
A contact form: Direct your comment to: Diversity, equity, and inclusion programs Message: I just wanted to give my heartfelt thanks for not bowing to political pressure & fascism and removing information about DEI etc., as certain other US-based academic societies have recently. Continuing to take the stance that diversity, equity, and inclusion are important and valuable has really reassured me that I've made the right choice in submitting to APS in the past, and in continuing to do so.
February 3, 2025 at 11:00 AM
jaredjeya.github.io
Meanwhile, on Apple TV:
A TV shows a hand writing some sort of pseudo-maths (in sharpie) involving modular arithmetic, with the dialogue “What if numbers didn’t behave the way we assumed?”
February 2, 2025 at 9:08 PM
jaredjeya.github.io
Feeling very cosy right now with @alessandraquig.bsky.social 🥰
Gracie (my partner’s family dog aka Captain Fat Fat) relaxing by the Christmas tree, on her dog bed. She’s brown with short, straight hair and floppy ears. The Christmas tree is lit up brightly in yellow lights, and covered in red and gold ornaments Another angle of Gracie. Alessandra (my partner) is lying with her head against Gracie’s A third angle of Gracie showing a fire in the background, with stockings hanging over it on the mantelpiece
December 10, 2024 at 3:49 AM
jaredjeya.github.io
Loving the barely-restrained disdain for the marketing hype exhibited by Dr Leek here

#QuantumComputing #physics

www.theguardian.com/technology/2...
“Quantum processors are peeling away at a double exponential rate and will continue to vastly outperform classical computers as we scale up,” said Hartmut Neven, the founder of the firm, who said that the latest test results, published on Monday in Nature magazine, “cracks a key challenge in quantum error correction that the field has pursued for almost 30 years”. He said the far greater speed of the new chip than classical computers “lends credence to the notion that quantum computation occurs in many parallel universes, in line with the idea that we live in a multiverse”. Simply put, if a quantum computer can be in many different states at once, it can get more done at the same time. Dr Peter Leek, research fellow at the University of Oxford’s Quantum Institute and founder of Oxford Quantum Circuits, said: “It’s definitely thought-provoking to put it that way. What it really does is show that quantum computing technology is rapidly moving forward. It really is working.” He described the Google results as a “shining example” of improvements in error correction, but he cautioned that the very fast processing results related to calculations that were “not of much real-world use”.
December 10, 2024 at 2:38 AM
jaredjeya.github.io
These were obtained using the time-dependent variational principle - this is a method that projects quantum dynamics onto a variational manifold, so you effectively get a semi-classical approximation within which you can observe *classical* chaos etc!

(I’ve put some more info in the alt text)
An illustration of TDVP. We consider a state in some variational manifold (black-bordered surface). The state ψ (red dot) will evolve under the full dynamics in the direction of -iHψ, however as we constrain ourselves to the manifold we project this down into the tangent space (blue plane) to the manifold at that point. This gives an optimal approximation to the full dynamics within the manifold. Over time, the state will move through the manifold (green line). This is also equivalent to the saddle-point approximation of the dynamics in the manifold, which is one way we can consider this to be a sort of semi-classical approximation. Image source: https://arxiv.org/abs/1807.01815
November 23, 2024 at 3:56 PM
jaredjeya.github.io
Who says that physics can’t also be art?

This was shared by a colleague in a seminar this morning - see if you can guess what it depicts!

🧪⚛️ #physics #quantum #SciArt
A section of a highly colourful plot, made up of many small coloured dots. In various spots, dense & regular concentric circles of different colours can be seen, surrounded by regions which appear more chaotic with many dots of different colours interleaving. Smaller circular (and less circular) regions can also be seen in between the larger ones, as well as on the edges of the large rings. The white background is barely visible.
November 22, 2024 at 3:37 PM
jaredjeya.github.io
Share your mug!

(I love conferences that give out free mugs)
A blue mug, from the Max Planck Institute for the Physics of Complex Systems. The Max Planck logo is on the left (some sort of Greco-Roman centurion head?) and a line drawing of the building is on the right. Some desk clutter is in the background of the shot.
November 5, 2024 at 12:03 PM
jaredjeya.github.io
If you see this, post a photo taken in the mountains
The view from the top of a multipitch climb in El Chorro, Spain. In the foreground, a rocky mountainside is visible, and in the background are green forested hills
November 1, 2024 at 10:30 AM
jaredjeya.github.io
Holy crap, look at the sky! ⚛️ #aurora #astronomy #physics
A view of aurora in the night sky. A bright red arc is visible, with a green one below it. The silhouette of trees is visible below the aurora and city lights are shining through the gaps. A view of aurora in the night sky. A bright red arc is visible, with a green one below it. The silhouette of trees is visible below the aurora and city lights are shining through the gaps. A view of aurora in the night sky. A bright red vertical line is visible, and a green “V” to the right of it. The silhouette of trees is visible below the aurora and city lights are shining through the gaps.
October 10, 2024 at 9:29 PM
jaredjeya.github.io
A real diagram from a real paper I’m reading right now!

#physics #AcademicChatter
A diagram featuring three drawings of turtles and an arrow labelling increasing “coupling K”. They get progressively more detailed (from outline sketch to coloured in + shaded) as K increases.
September 29, 2024 at 5:05 PM
jaredjeya.github.io
I’m now officially a contributor to python’s numba package 🤓
A screenshot of a commit to numba, merging my pull request. “Merge pull request #9338 from jaredjeya/add-setops1d” “Add np.in1d, np.isin, np.setxor1d, пр.setdiff1d, extend np.intersect1d”
September 24, 2024 at 12:18 PM
jaredjeya.github.io
Messing about with iOS’s new Maths Notes feature and apparently it’s fairly easy to completely lock up the app 😅

#maths #iOS18
A screenshot of the iOS notes app, with three equations: “y = x”, “y = x*x -3”, and “y = sin(e^x” [sic - I couldn’t type the closing bracket!] Below is a graph faithfully rendering these three equations. The final line starts at zero on the left and, on approaching the x axis in the centre, starts to oscillate, rapidly becoming a solid mass between -1 and 1.
September 22, 2024 at 11:34 AM
jaredjeya.github.io
Post a butterfly to celebrate 10 million users on Bluesky! 🦋

This is Hofstadter’s Butterfly, a fractal that emerges from plotting the energy spectrum of a charged particle moving in a square lattice in the presence of a magnetic field. Quantum physics can be beautiful too!

#physics 🧪 ⚛️
Hofstadter’s Butterfly. Four lines meet at a point in the middle, and these then break apart into fractal structures as you move away from the centre. There’s a beautiful symmetry to the whole picture. Experimental verification of the butterfly. It looks a lot more like a butterfly than the theoretical picture! You can see four wing-like lobes branching off from the centre.
September 21, 2024 at 6:15 PM
jaredjeya.github.io
At the Localisation conference at MPI Dresden - posters are up! 🧪⚛️ #physics #locali24
A poster based on our recent paper - Hilbert space fragmentation at the origin of disorder-free localization in the lattice Schwinger model Click the link in my bio to find it! A poster based on my paper “Renormalization view on resonance proliferation between many-body localized phases” - check the link in my bio to read it!
September 17, 2024 at 5:28 PM
jaredjeya.github.io
What does this all mean?

Our results suggest apparent signatures of a many-body localised (MBL) phase can be accounted for by a single phase deriving from the observed fragmentation in the infinite-coupling limit, rather than the mechanisms of conventional disorder-driven MBL

(6/7)
Schematic phase diagram for the 1D lattice Schwinger model as a function of the dimensionless coupling ratio J/w. In the weak-coupling limit J/w → 0, the model reduces to an integrable XY spin chain. In the thermodynamic limit, any finite J breaks integrability, resulting in a chaotic phase. Around J/w ∼ 1, an ergodicity breaking transition, consistent with an onset of MBL, has previously been observed. However, the nature and extent of MBL phase is difficult to ascertain in finite-size systems due to its proximity to the regime dominated by Hilbert space fragmentation. The latter is exact at J/w → ∞ and, as shown in this paper, strongly affects the properties of numerically accessible systems even at J/w ∼ 10.
September 17, 2024 at 8:29 AM
jaredjeya.github.io
We find that the claimed ultra-slow entanglement growth results from this fragmentation, and show (including with matrix product state simulations) that is more naturally explained by a single-log at short times with a slow power-law relaxation to a finite-size saturation value at late times:

(5/7)
Growth of entanglement entropy from the |vac⟩ initial state for system size N = 50 at J/w = 3, obtained via MPS simulations (see Methods for details). The data is averaged over 600 background charge sectors, with the standard deviation represented by the shading. The dashed lines indicate different types of fits summarized in the legend. In the inset, we show the same data on a log-log scale. Sector-averaged configurational entropy, S_C(t), for J = 8 and system sizes N = 8, 10, 12, 14, 16 (solid lines). For each N we fit a power-law of the form S_C(t) = S_∞ − S_0 t^(−α) (dotted lines). In the inset, we show the power-law decay towards the fitted saturation value, ∆S_C = S_∞ − S_C (t) for N ≥ 10. We find the power-law exponent seems to tend towards 0 with increasing N and J, suggesting that this might be going towards a standard log law - or alternatively, that we can no longer access the saturation regime with finite time numerics.
September 17, 2024 at 8:26 AM