Dr Jared Jeyaretnam ⚛đŸ§Ș

@jaredjeya.github.io

851 Followers 491 Following

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 PS: All opinions solely my own.

A piece of paper parodying the official University of Nottingham logo, reading "University of Nothingham: No course, No research, No Staff". The tower in the original logo has been replaced by one that is crumbling and cracked.
(a) Final snapshots for the local density and instantaneous currents measured on the H1-1 device for fermions with V = 0,ϕ = 0 (m = 14 timesteps, ∆t = 0.21), and (b) for V = 0,ϕ= π/2 (m = 16 timesteps, ∆t = 0.27). Both snapshots were averaged over 1480 trajectories.
FIG. 1. (a) The setup consists of a 4 × 4 square lattice with nearest neighbour hopping (directed arrows) and interactions (dashed line). Stochastic driving acts on the two corner sites labelled “source” (red) and “drain” (blue) with probability p. (b) Schematic of the quantum trajectory realised by our driving scheme, showing the local density on the source (top) and the total particle number (bottom). The black line is a single trajectory, with source and drain jumps indicated by dashed lines, and grey line indicates the average. (c) The corresponding circuit starts with unitary state preparation followed by unitary evolution using a Trotter decomposition. The non-unitary step uses an ancilla qubit for a “quantum coin flip” with probability p that classically conditions a measurement and reset on the source and drain. After m timesteps of the unitary and non-unitary drive we perform a full-circuit measurement to extract observables such as local densities and currents
A brown, rounded bun with icing on it. The icing reads, in terrible handwriting, Hψ = i dψ/dt
A still from the new Spider-Man trailer. It shows Bruce Banner (played by Mark Ruffalo) standing in front of a presentation slide on “Lattice Quantum Chromodynamics (QCD)”, although he’s standing in the way of most of it
A fake headline by Allister Heath reading: The elite's fanatical obsession with quantum computing borders on a religious cult
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.
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.
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
”
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
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 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!)
A spacetime diagram described in the next tweet
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
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!
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.
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?”
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
“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.
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
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.
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.
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
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 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.
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”
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.
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.
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!
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.
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.
(a) The parity P over some region gives the total charge in the original gauge theory; this must sum to zero over the whole chain. (b) Exchanging |10⟩ ↔ |01⟩ at sites 2ℓ and 2ℓ + 1 creates an e−e+ pair. This is resonant if the gauge field L_2ℓ = 0, i.e. if the fermionic and background charges sum to zero. (c) For a particular charge sector and spin configuration, only certain bonds satisfy the previous condition and thus permit dynamics in the large-J limit. These “active regions” are independent and so the effective Hamiltonian is a sum of local commuting terms.
From Brenes, Dalmonte, Heyl, and Scardicchio, "Many-Body Localization Dynamics from Gauge Invariance", PRL 120, 030601 (2018): (c) Long-time growth of S_A(t) for J = 10 including a fit (solid line) f(t) a log[log(wt) + b to the N = 14 data. (d) The same data are plotted on a double logarithmic scale.
The 1D lattice Schwinger model (top) describes quantum electrodynamics on a lattice. Fermionic degrees of freedom ψ_n on odd (even) sites represent the presence or absence of an electron (positron), while the electric fields L_n reside on the bonds and mediate coupling between the particles. In 1D, one can integrate out the fields and apply a Jordan-Wigner transform, which results in a an XY-type model for spins σ =↑, ↓. The dynamical fields are replaced by static background charges q_n, which act as a disorder potential for spins.
Donald Trump at the debate saying, “I have concepts of a plan”
My parents! Description: Jared, grinning, in a grey and red PhD gown and wearing a black academic cap (not a mortarboard! but a round, baggy hat with a hard wide brim). He’s flanked by his parents.
A picture of a research poster with a red & blue colour plot in the centre. A caption reads “Wiggliness of OTOCs in energy eigenstates averaged over near levels in the spectrum” and an arrow points out “wiggliness suppressed by chaos”
A laptop with an assortment of stickers in a variety of colours, ranging from political/social causes, to bands, holiday destinations, webcomic characters, climbing gyms, and of course, Qiskit (and I think Phasecraft?), whose logo is a stylised Bloch sphere
Aurora Borealis: beautiful purple and green hues in bands, with silhouettes of trees and fencing in the foreground.
An absolutely incredible night sky with the Milky Way clearly visible. (Unfortunately I’d find it hard to do it justice here - I’m not a poet!)
Two cats stretch out on a red brick pavement next to a wall; one is white and grey, the other beige.
The worst plot you’ve ever seen. Multicoloured crosses are overlaid on multicoloured lines on top of density contours on top of triangles with error bars, with chunky histograms on the left and smooth ones on the bottom. There is text everywhere, some of it totally illegible, and a random colourbar. It keeps getting worse as you look more closely, with additional layers revealing themselves.
Quantum supercomputer to tackle train delays in UK trial Department for Transport to test algorithm designed to improve timetables and reduce disruption James Titcomb 12 February 2024 ‱ 1:21pm A quantum supercomputer will be used to find ways to make Britain's trains run on time under tests from the Department for Transport aimed at overhauling rail schedules.
Cloud of words in various colors and sizes based on the Google Scholar profile for Jared Jeyaretnam. Some of the largest words include quantum breaking bulk coherence ergodicity localized many-body order phase phases proliferation renormalization resonance scars stabilisation symmetry-protected topological view
A screenshot of the UCL thesis deposit website showing a download button labelled “FINAL_THESIS.pdf”.
A postcard for “Glentanglement, Scotland’s Quantum Valley”: a map of Scotland overlaid with a number of logos of quantum computing startups and universities, with the conspicuous addition of BP off to the side.