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The Schrodinger cat's Post

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Sharing the latest developments in the world of quantum science. I am not a bot. In the real life, I am Adrien Devolder (@adriendevolder), research associate in quantum control at the University of Toronto.

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The Schrodinger cat's Post @schrodcatpost.bsky.social · Nov 22

Back on Bluesky!
Discover the latest developments in quantum science and technology here!
Every day, we will post a selection of interesting arXiv articles and share significant updates from the industry.
Stay updated of the quantum revolution by following us!

The Schrodinger cat's Post @schrodcatpost.bsky.social · 7h

That’s it for the daily selection. If you enjoyed it, please consider giving me a like or reposting to support my content. Thanks! (Remember that these papers are published on arXiv before undergoing any peer review.)

The Schrodinger cat's Post @schrodcatpost.bsky.social · 7h

A new compiler for hybrid oscillator–qubit systems has been introduced. They use Generalized Quantum Signal Processing to construct arbitrary bosonic phase gates. This allows the simulation of physical systems whose potentials are complicated.
arxiv.org/abs/2510.10495

Oscillator-qubit generalized quantum signal processing for vibronic models: a case study of uracil cation

Hybrid oscillator-qubit processors have recently demonstrated high-fidelity control of both continuous- and discrete-variable information processing. However, most of the quantum algorithms remain lim...

The Schrodinger cat's Post @schrodcatpost.bsky.social · 7h

A new hybrid optimization method uses the continuous convex solution of a combinatorial problem to define a restricted discrete search region, allowing a compact QUBO encoding that reduces qubit count and improves quantum annealing performance.
arxiv.org/abs/2510.11153

Hot-Starting Quantum Portfolio Optimization

Combinatorial optimization with a smooth and convex objective function arises naturally in applications such as discrete mean-variance portfolio optimization, where assets must be traded in integer qu...

The Schrodinger cat's Post @schrodcatpost.bsky.social · 7h

Two emulation backends of neutral quantum hardware has been introduced by Pasqal, enabling researchers to efficiently and accurately model the dynamics of large neutral atom quantum systems, for algorithm design, benchmarking, and hardware validation.
arxiv.org/abs/2510.09813

Efficient Emulation of Neutral Atom Quantum Hardware

Simulating the dynamics of neutral atom arrays is a challenging problem. To address this, we introduce two emulators, emu-sv and emu-mps, as computational backends for Pasqal's pulser package. Emu-sv ...

The Schrodinger cat's Post @schrodcatpost.bsky.social · 7h

A new paper transforms random circuit sampling from a “quantum supremacy” test into a scalable diagnostic and benchmarking tool that infers detailed spatiotemporal and correlated error structures directly from experimental data.
arxiv.org/abs/2510.09919

How much can we learn from quantum random circuit sampling?

Benchmarking quantum devices is a foundational task for the sustained development of quantum technologies. However, accurate in situ characterization of large-scale quantum devices remains a formidabl...

The Schrodinger cat's Post @schrodcatpost.bsky.social · 7h

Hierarchical Qubit-Merging Transformer (HQMT) is a new structure-aware, multi-scale transformer decoder that leverages the stabilizer graph of surface codes, outperforming both classical and neural decoders across code distances.
arxiv.org/abs/2510.11593

Hierarchical Qubit-Merging Transformer for Quantum Error Correction

For reliable large-scale quantum computation, a quantum error correction (QEC) scheme must effectively resolve physical errors to protect logical information. Leveraging recent advances in deep learni...

The Schrodinger cat's Post @schrodcatpost.bsky.social · 7h

Today #quantum article selection:
- Transformers for QEC decoding
- Benchmark with quantum random circuit sampling
- Emulation of neutral atom quantum processor
- Warm start of portfolio optimization
- Oscillator-qubit quantum compiler

More details and links below:

The Schrodinger cat's Post @schrodcatpost.bsky.social · 8h

That’s it for the daily selection. If you enjoyed it, please consider giving me a like or reposting to support my content. Thanks! (Remember that these papers are published on arXiv before undergoing any peer review.)

The Schrodinger cat's Post @schrodcatpost.bsky.social · 8h

A new block-encoding constructions for many-body Hamiltonians reduce T-gate scaling from linear to sublinear, and lower ancilla and normalization overhead.
arxiv.org/abs/2510.08644

Block encoding with low gate count for second-quantized Hamiltonians

Efficient block encoding of many-body Hamiltonians is a central requirement for quantum algorithms in scientific computing, particularly in the early fault-tolerant era. In this work, we introduce new...

The Schrodinger cat's Post @schrodcatpost.bsky.social · 8h

Conventional measurement error mitigation (via inverse calibration matrices) introduces systematic overcorrections when state preparation errors are present, leading to exponentially increasing bias in large systems.
arxiv.org/abs/2510.08687

The Exponential Deviation Induced by Quantum Readout Error Mitigation

The error mitigation techniques are indispensable for the noisy intermediate-scale quantum devices to obtain the experimental data with reasonable precision. The method based on taking the inverse of ...

The Schrodinger cat's Post @schrodcatpost.bsky.social · 8h

A new paper develops a method to implement noise-adapted (Petz) quantum error correction using syndrome measurements, demonstrates it for amplitude-damping noise on IBM hardware, and achieves up to 3× improvement in qubit lifetime.
arxiv.org/abs/2510.08719

Universal syndrome-based recovery for noise-adapted quantum error correction

Quantum error correction (QEC) is an essential tool for quantum computing that enables reliable information processing in the presence of noise. Syndrome measurements play a central role in QEC, makin...

The Schrodinger cat's Post @schrodcatpost.bsky.social · 8h

A GHZ state of 120 superconducting qubits was prepared by IBM researchers, the largest ever achieved. They used error detection, allowing them to discard erroneous runs.
arxiv.org/abs/2510.09520

Big cats: entanglement in 120 qubits and beyond

Entanglement is the quintessential quantum phenomenon and a key enabler of quantum algorithms. The ability to faithfully entangle many distinct particles is often used as a benchmark for the quality o...

The Schrodinger cat's Post @schrodcatpost.bsky.social · 8h

I was off yesterday due to the the Canadian Thanksgiving. Here, it is the selection of yesterday article:
- 120-qubit GHZ state
- Noise-adapted QEC
- Limits of quantum readout error mitigation
- Quantum simulation with low T-count

More details and links below:

The Schrodinger cat's Post @schrodcatpost.bsky.social · 9h

The Schrodinger Cat post was off yesterday due to the Canadian Thanksgiving. Today, there will be the selections of the arXiv articles of yesterday and today. Stay tuned!

The Schrodinger cat's Post @schrodcatpost.bsky.social · 5d

That’s it for the daily selection. If you enjoyed it, please consider giving me a like or reposting to support my content. Thanks! (Remember that these papers are published on arXiv before undergoing any peer review.)

The Schrodinger cat's Post @schrodcatpost.bsky.social · 5d

A new article shows that n-qubit Toffoli gates can be implemented with exponentially fewer T gates by allowing a tiny error, using randomized Clifford+T circuits.
arxiv.org/abs/2510.07223

Multi-qubit Toffoli with exponentially fewer T gates

Prior work of Beverland et al. has shown that any exact Clifford+$T$ implementation of the $n$-qubit Toffoli gate must use at least $n$ $T$ gates. Here we show how to get away with exponentially fewer...

The Schrodinger cat's Post @schrodcatpost.bsky.social · 5d

A new paper presents a method to convert matrix product states (MPS) into quantum circuits, allowing preparation of ground and excited states on quantum devices.
arxiv.org/abs/2510.07125

Preparation of initial states with open and periodic boundary conditions on quantum devices using matrix product states

We present a framework for preparing quantum states from matrix product states (MPS) with open and periodic boundary conditions on quantum devices. The MPS tensors are mapped to unitary gates, which a...

The Schrodinger cat's Post @schrodcatpost.bsky.social · 5d

Given a set of observed error syndromes, a decoder tries to infer the underlying errors and correct them. A new work introduces QuBA, a Bayesian graph neural decoder, and SAGU, a multi-code training framework, to improve decoding.
arxiv.org/abs/2510.06257

Toward Uncertainty-Aware and Generalizable Neural Decoding for Quantum LDPC Codes

Quantum error correction (QEC) is essential for scalable quantum computing, yet decoding errors via conventional algorithms result in limited accuracy (i.e., suppression of logical errors) and high ov...

The Schrodinger cat's Post @schrodcatpost.bsky.social · 5d

A new work presents a fault-tolerant quantum algorithm for topology optimization in structural mechanics, using Grover’s algorithm for global search and quantum linear algebra techniques (block-encoding, QSVT, and amplitude estimation).
arxiv.org/abs/2510.07280

End-to-End Quantum Algorithm for Topology Optimization in Structural Mechanics

Topology optimization is a key methodology in engineering design for finding efficient and robust structures. Due to the enormous size of the design space, evaluating all possible configurations is ty...

The Schrodinger cat's Post @schrodcatpost.bsky.social · 5d

A new article introduces a continuous-variable analogue of the Pauli propagation algorithm, called Displacement Propagation. Surprisingly, non-Gaussianity and symplectic coherence can make the system easier to simulate when noise is present.
arxiv.org/abs/2510.07264

When quantum resources backfire: Non-gaussianity and symplectic coherence in noisy bosonic circuits

Analyzing the impact of noise is of fundamental importance to understand the advantages provided by quantum systems. While the classical simulability of noisy discrete-variable systems is increasingly...

The Schrodinger cat's Post @schrodcatpost.bsky.social · 5d

Today #quantum article selection:
- Classical simulation of noisy bosonic circuit
- Quantum algorithm for structural mechanics
- QEC decoder using neural network
- Mapping between MPS states and quantum circuits
- Optimization of T-count

More details and links below:

The Schrodinger cat's Post @schrodcatpost.bsky.social · 6d

That’s it for the daily selection. If you enjoyed it, please consider giving me a like or reposting to support my content. Thanks! (Remember that these papers are published on arXiv before undergoing any peer review.)

The Schrodinger cat's Post @schrodcatpost.bsky.social · 6d

The 2D Fermi-Hubbard model can be simulated by a hybrid quantum–classical approach. The authors reformulate the model into coupled fermionic and spin subsystems and solve them self-consistently.
arxiv.org/abs/2510.05897

Hybrid quantum-classical analog simulation of two-dimensional Fermi-Hubbard models with neutral atoms

We experimentally study the two-dimensional Fermi-Hubbard model using a Rydberg-based quantum processing unit in the analog mode. Our approach avoids encoding directly the original fermions into qubit...

The Schrodinger cat's Post @schrodcatpost.bsky.social · 6d

A new family of self-dual bivariate bicycle codes combines the high-rate, low-overhead properties of bivariate bicycle codes with the transversal Clifford gates of color codes.
arxiv.org/abs/2510.05211

Self-dual bivariate bicycle codes with transversal Clifford gates

Bivariate bicycle codes are promising candidates for high-threshold, low-overhead fault-tolerant quantum memories. Meanwhile, color codes are the most prominent self-dual CSS codes, supporting transve...

The Schrodinger cat's Post @schrodcatpost.bsky.social · 6d

Gradient-based optimization is the engine of variational quantum computing. The author of a new article generalizes the parameter-shift rule for any generators with complex spectra.
arxiv.org/abs/2510.05289

Overshifted Parameter-Shift Rules: Optimizing Complex Quantum Systems with Few Measurements

Gradient-based optimization is a key ingredient of variational quantum algorithms, with applications ranging from quantum machine learning to quantum chemistry and simulation. The parameter-shift rule...