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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 · 1d

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 · 1d

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 · 1d

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 · 1d

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 · 1d

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 · 1d

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 · 1d

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 · 2d

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 · 2d

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 · 2d

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 · 2d

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...

The Schrodinger cat's Post @schrodcatpost.bsky.social · 2d

A new general, efficient post-selection method for quantum LDPC codes improves the reliability of quantum error correction. Using cluster-based confidence measures, simulations on several code families show orders-of-magnitude reduction in logical error rates.
arxiv.org/abs/2510.05795

Efficient Post-Selection for General Quantum LDPC Codes

Post-selection strategies that discard low-confidence computational results can significantly improve the effective fidelity of quantum error correction at the cost of reduced acceptance rates, which ...

The Schrodinger cat's Post @schrodcatpost.bsky.social · 2d

A new article introduces batched fault-tolerant operations for high-rate quantum LDPC codes, enabling the same logical gate to be applied across many encoded qubits in parallel.
arxiv.org/abs/2510.06159

Batched high-rate logical operations for quantum LDPC codes

High-rate quantum LDPC (qLDPC) codes reduce memory overhead by densely packing many logical qubits into a single block of physical qubits. Here we extend this concept to high-rate computation by const...

The Schrodinger cat's Post @schrodcatpost.bsky.social · 2d

Today #quantum article selection:
- Batched high-rate logical operations
- Hybrid quantum-classical analog simulation
- Improved post-selection for QEC code
- Generalized parameter-shift rule
- New family of QEC code

More details and links below:

The Schrodinger cat's Post @schrodcatpost.bsky.social · 3d

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 · 3d

A new work develop a filtered-state preparation framework that amplifies the overlap of an initial quantum state with a target eigenstate using spectral filters.

arxiv.org/abs/2510.04294

Filtered Quantum Phase Estimation

Accurate state preparation is a critical bottleneck in many quantum algorithms, particularly those for ground state energy estimation. Even in fault-tolerant quantum computing, preparing a quantum sta...

The Schrodinger cat's Post @schrodcatpost.bsky.social · 3d

A new article proposes a bosonic quantum error-correcting code built from superpositions of squeezed Fock states. This code achieves exact orthogonality and protects against both single-photon loss and dephasing.
arxiv.org/abs/2510.04209

Quantum Error Correction with Superpositions of Squeezed Fock States

Bosonic codes, leveraging infinite-dimensional Hilbert spaces for redundancy, offer great potential for encoding quantum information. However, the realization of a practical continuous-variable bosoni...

The Schrodinger cat's Post @schrodcatpost.bsky.social · 3d

A new study shows that trapped ions can act as self-sensing probes to measure and optimize the laser beams that control them, using the four-photon Stark shift.
arxiv.org/abs/2510.03966

Ion-Based Characterization of Laser Beam Profiles for Quantum Information Processing

Laser-driven operations are a common approach for engineering one- and two-qubit gates in trapped-ion arrays. Measuring key parameters of these lasers, such as beam sizes, intensities, and polarizatio...

The Schrodinger cat's Post @schrodcatpost.bsky.social · 3d

A new work propose H-VEC, a hybrid protocol that turns any classical bit-flip code into a quantum code capable of correcting all Pauli errors, at the expense of more classical sampling.
arxiv.org/abs/2510.05008

Correcting quantum errors using a classical code and one additional qubit

Classical error-correcting codes are powerful but incompatible with quantum noise, which includes both bit-flips and phase-flips. We introduce Hadamard-based Virtual Error Correction (H-VEC), a protoc...

The Schrodinger cat's Post @schrodcatpost.bsky.social · 3d

A new paper shows simulating fermions on qubit-based quantum computers can be done much more efficiently than previously thought using a new way to perform fermionic permutations in the Jordan–Wigner and related encodings.
arxiv.org/abs/2510.05099

Simulating fermions with exponentially lower overhead

Simulating time evolution under fermionic Hamiltonians is a compelling application of quantum computers because it lies at the core of predicting the properties of materials and molecules. Fermions ca...

The Schrodinger cat's Post @schrodcatpost.bsky.social · 3d

Today #quantum article selection:
- Optimized fermion-to-qubit mapping
- QEC using a classical code and one additional qubit
- Calibration of ion processors
- QEC with superposition of squeezed Fock states
- Filtered QPE

More details and links below:

The Schrodinger cat's Post @schrodcatpost.bsky.social · 3d

Nobel Prize in Physics for the works that made superconducting qubits possible!
www.nobelprize.org

The Schrodinger cat's Post @schrodcatpost.bsky.social · 4d

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 · 4d

A new article shows that variational quantum algorithms based on boson sampling can be made much faster and easier to optimize by constraining the phase shifters to have only two distinct eigenvalues. This simple restriction removes local minima and barren plateaus.
arxiv.org/abs/2510.02430

Mitigating the barren plateau problem in linear optics

We demonstrate a significant speedup of variational quantum algorithms that use discrete variable boson sampling when the parametrised phase shifters are constrained to have two distinct eigenvalues. ...

The Schrodinger cat's Post @schrodcatpost.bsky.social · 4d

A new study developed a new variational method called Pauli Path Simulation to efficiently generate circuits that approximate ground states of complex quantum systems. They applied it to models with over 100 qubits, achieving near-exact agreement with classical benchmarks.
arxiv.org/abs/2510.02428

Utility-Scale Quantum State Preparation: Classical Training using Pauli Path Simulation

We use Pauli Path simulation to variationally obtain parametrized circuits for preparing ground states of various quantum many-body Hamiltonians. These include the quantum Ising model in one dimension...