Physics for AI

Quantum Physics

Quantum Matter

At DeepPsi we develop frontier AI for quantum science.

Built around the group of Prof. Liang Fu at MIT, our mission is to transform quantum physics and material science with a new generation of AI.

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Attention is all you need to solve chiral superconductivity

Chun-Tse Li, Tzen Ong, Max Geier, Hsin Lin, Liang Fu

Recent advances on neural quantum states have shown that correlations between quantum particles can be efficiently captured by attention-- a foundation of modern neural architectures that enables neural networks to learn the relation between objects. In this work, we show that a general-purpose self-attention Fermi neural network is able to find chiral px±ipy superconductivity in an attractive Fermi gas by energy minimization, {\it without prior knowledge or bias towards pairing}. The superconducting state is identified from the optimized wavefunction by measuring various physical observables: the pair binding energy, the total angular momentum of the ground state, and off-diagonal long-range order in the two-body reduced density matrix. Our work paves the way for AI-driven discovery of unconventional and topological superconductivity in strongly correlated quantum materials.

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Artificial Intelligence for Quantum Matter: Finding a Needle in a Haystack

Khachatur Nazaryan, Filippo Gaggioli, Yi Teng, Liang Fu

Neural networks (NNs) have great potential in solving the ground state of various many-bodyproblems. However, several key challenges remain to be overcome before NNs can tackle problemsand system sizes inaccessible with more established tools. Here, we present a general and efficientmethod for learning the NN representation of an arbitrary many-body complex wave function fromits N-particle probability density and probability current density. Having reached overlaps as largeas 99.9%, we employ our neural wave function for pre-training to effortlessly solve the fractionalquantum Hall problem with Coulomb interactions and realistic Landau-level mixing for as manyas 25 particles. Our work demonstrates efficient, accurate simulation of highly-entangled quantummatter using general-purpose deep NNs enhanced with physics-informed initialization.

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Is attention all you need to solve the correlated electron problem?

Max Geier, Khachatur Nazaryan, Timothy Zaklama, Liang Fu

The attention mechanism has transformed artificial intelligence research by its ability to learn relations between objects. In this work, we explore how a many-body wavefunction ansatz constructed from a large-parameter self-attention neural network can be used to solve the interacting electron problem in solids. By a systematic neural-network variational Monte Carlo study on a moiré quantum material, we demonstrate that the self-attention ansatz provides an accurate and efficient solution without human bias. Moreover, our numerical study finds that the required number of variational parameters scales roughly as N2 with the number of electrons, which opens a path towards efficient large-scale simulations.

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