The Schrodinger cat's Post
@schrodcatpost.bsky.social
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.
I am not a bot. In the real life, I am Adrien Devolder (@adriendevolder), research associate in quantum control at the University of Toronto.
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.)
November 27, 2025 at 5:09 PM
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.)
Gate-based variational quantum algorithms can tackle real-world portfolio optimization by encoding multiple assets per qubit and partitioning highly correlated sub-portfolios. This approach enables scalable quantum solutions for over 250 assets.
arxiv.org/abs/2511.21305
arxiv.org/abs/2511.21305
Large-scale portfolio optimization using Pauli Correlation Encoding
Portfolio optimization is a cornerstone of financial decision-making, traditionally relying on classical algorithms to balance risk and return. Recent advances in quantum computing offer a promising a...
arxiv.org
November 27, 2025 at 5:09 PM
Gate-based variational quantum algorithms can tackle real-world portfolio optimization by encoding multiple assets per qubit and partitioning highly correlated sub-portfolios. This approach enables scalable quantum solutions for over 250 assets.
arxiv.org/abs/2511.21305
arxiv.org/abs/2511.21305
An asymmetric SQUID can function as a coherent superconducting diode, realizing nonreciprocal qubit–qubit coupling. The authors implemented a tunable, nonreciprocal half-iSWAP gate.
arxiv.org/abs/2511.20758
arxiv.org/abs/2511.20758
Nonreciprocal quantum information processing with superconducting diodes in circuit quantum electrodynamics
Introducing new components and functionalities into quantum devices is critical in advancing state-of-the-art hardware. Here, we propose superconducting diodes (SDs) as a coherent nonreciprocal elemen...
arxiv.org
November 27, 2025 at 5:09 PM
An asymmetric SQUID can function as a coherent superconducting diode, realizing nonreciprocal qubit–qubit coupling. The authors implemented a tunable, nonreciprocal half-iSWAP gate.
arxiv.org/abs/2511.20758
arxiv.org/abs/2511.20758
A new compilation pipeline maps quantum algorithms onto surface-code lattice-surgery circuits and uses it to determine when error correction actually improves performance. Their simulations show that small QAOA and QPE circuits reach break-even on near-term hardware.
arxiv.org/abs/2511.20947
arxiv.org/abs/2511.20947
Compilation Pipeline for Predicting Algorithmic Break-Even in an Early-Fault-Tolerant Surface Code Architecture
Recent experimental progress in realizing surface code on hardware, including demonstrations of break-even logical memory on devices with up to hundreds of physical qubits, has materially advanced the...
arxiv.org
November 27, 2025 at 5:09 PM
A new compilation pipeline maps quantum algorithms onto surface-code lattice-surgery circuits and uses it to determine when error correction actually improves performance. Their simulations show that small QAOA and QPE circuits reach break-even on near-term hardware.
arxiv.org/abs/2511.20947
arxiv.org/abs/2511.20947
A new purification-inspired protocol suppresses non-Markovian (memory-bearing) noise without requiring any knowledge or calibration of the noise model, achieving exponential error reduction by increasing the number of ancilla qubits.
arxiv.org/abs/2511.20304
arxiv.org/abs/2511.20304
Realizing Universal Non-Markovian Noise Suppression
Non-Markovian noise, arising from environmental memory effects, is the most general and challenging form of noise in quantum computing, and is typically difficult to characterize and suppress. Here, w...
arxiv.org
November 27, 2025 at 5:09 PM
A new purification-inspired protocol suppresses non-Markovian (memory-bearing) noise without requiring any knowledge or calibration of the noise model, achieving exponential error reduction by increasing the number of ancilla qubits.
arxiv.org/abs/2511.20304
arxiv.org/abs/2511.20304
A new article proposes a new way to implement fault-tolerant continuous-angle rotation gates directly in stabilizer codes by exploiting the structure of realistic noise, thereby bypassing costly T-gate compilation and magic-state distillation.
arxiv.org/abs/2511.19983
arxiv.org/abs/2511.19983
Error-structure-tailored early fault-tolerant quantum computing
Fault tolerance is widely regarded as indispensable for achieving scalable and reliable quantum computing. However, the spacetime overhead required for fault-tolerant quantum computating remains prohi...
arxiv.org
November 27, 2025 at 5:09 PM
A new article proposes a new way to implement fault-tolerant continuous-angle rotation gates directly in stabilizer codes by exploiting the structure of realistic noise, thereby bypassing costly T-gate compilation and magic-state distillation.
arxiv.org/abs/2511.19983
arxiv.org/abs/2511.19983
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.)
November 21, 2025 at 1:57 PM
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.)
A new review by @mvscerezo.bsky.social and Su Yeon Chang gives a bird's-eye view of quantum machine learning. It clearly presents the main concepts and challenges in this field, which has generated significant hype around the prospect of quantum advantage.
arxiv.org/abs/2511.15969
arxiv.org/abs/2511.15969
A Primer on Quantum Machine Learning
Quantum machine learning (QML) is a computational paradigm that seeks to apply quantum-mechanical resources to solve learning problems. As such, the goal of this framework is to leverage quantum proce...
arxiv.org
November 21, 2025 at 1:57 PM
A new review by @mvscerezo.bsky.social and Su Yeon Chang gives a bird's-eye view of quantum machine learning. It clearly presents the main concepts and challenges in this field, which has generated significant hype around the prospect of quantum advantage.
arxiv.org/abs/2511.15969
arxiv.org/abs/2511.15969
A new work explores how to efficiently encode real financial data into quantum states. The authors use the Genetic Algorithm for State Preparation (GASP), achieving higher encoding fidelity, fewer gates, and lower circuit depth.
arxiv.org/abs/2511.15739
arxiv.org/abs/2511.15739
Genetically Engineered Quantum Circuits for Financial Market Indicators
Quantum computing holds immense potential for transforming financial analysis and decision-making. Realising this potential necessitates the efficient encoding and processing of financial data on quan...
arxiv.org
November 21, 2025 at 1:57 PM
A new work explores how to efficiently encode real financial data into quantum states. The authors use the Genetic Algorithm for State Preparation (GASP), achieving higher encoding fidelity, fewer gates, and lower circuit depth.
arxiv.org/abs/2511.15739
arxiv.org/abs/2511.15739
TRAM is a new compiler technique for qubit mapping that explicitly takes into account T₂ decoherence times when assigning logical qubits to physical ones. TRAM shows improvements over the state-of-the-art SABRE algorithm in both fidelity and circuit depth.
arxiv.org/abs/2511.16051
arxiv.org/abs/2511.16051
TRAM: A Transverse Relaxation Time-Aware Qubit Mapping Algorithm for NISQ Devices
Noisy intermediate-scale quantum (NISQ) devices impose dual challenges on quantum circuit execution: limited qubit connectivity requires extensive SWAP-gate routing, while time-dependent decoherence p...
arxiv.org
November 21, 2025 at 1:57 PM
TRAM is a new compiler technique for qubit mapping that explicitly takes into account T₂ decoherence times when assigning logical qubits to physical ones. TRAM shows improvements over the state-of-the-art SABRE algorithm in both fidelity and circuit depth.
arxiv.org/abs/2511.16051
arxiv.org/abs/2511.16051
A new paper proposes using reinforcement learning (RL) to automatically generate ansätze based on molecular identity and geometry. The generated circuits adapt smoothly to bond distance, and the learned structures can even be physically interpretable.
arxiv.org/abs/2511.16559
arxiv.org/abs/2511.16559
Reinforcement learning of quantum circuit architectures for molecular potential energy curves
Quantum chemistry and optimization are two of the most prominent applications of quantum computers. Variational quantum algorithms have been proposed for solving problems in these domains. However, th...
arxiv.org
November 21, 2025 at 1:57 PM
A new paper proposes using reinforcement learning (RL) to automatically generate ansätze based on molecular identity and geometry. The generated circuits adapt smoothly to bond distance, and the learned structures can even be physically interpretable.
arxiv.org/abs/2511.16559
arxiv.org/abs/2511.16559
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.)
November 20, 2025 at 5:06 PM
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 ultimate goal of quantum error correction is to create logical qubits with very low error rates. This leads to a rare-event regime. A recent work developed three methods to study the rare-event regime for qLDPC codes.
arxiv.org/abs/2511.15177
arxiv.org/abs/2511.15177
Fail fast: techniques to probe rare events in quantum error correction
The ultimate goal of quantum error correction is to create logical qubits with very low error rates (e.g. 1e-12) and assemble them into large-scale quantum computers capable of performing many (e.g. b...
arxiv.org
November 20, 2025 at 5:06 PM
The ultimate goal of quantum error correction is to create logical qubits with very low error rates. This leads to a rare-event regime. A recent work developed three methods to study the rare-event regime for qLDPC codes.
arxiv.org/abs/2511.15177
arxiv.org/abs/2511.15177
Quantum advantage has been demonstrated in Gaussian boson sampling. A new emulator can simulate 100-mode Gaussian boson sampling experiments on a single GPU. Therefore, this work challenges assumptions about the classical intractability of certain quantum sampling tasks.
arxiv.org/abs/2511.14923
arxiv.org/abs/2511.14923
A fast and frugal Gaussian Boson Sampling emulator
If classical algorithms have been successful in reproducing the estimation of expectation values of observables of some quantum circuits using off-the-shelf computing resources, matching the performan...
arxiv.org
November 20, 2025 at 5:06 PM
Quantum advantage has been demonstrated in Gaussian boson sampling. A new emulator can simulate 100-mode Gaussian boson sampling experiments on a single GPU. Therefore, this work challenges assumptions about the classical intractability of certain quantum sampling tasks.
arxiv.org/abs/2511.14923
arxiv.org/abs/2511.14923
Standard Trotter-Suzuki decompositions approximate quantum time evolution but can be inaccurate and require many gates. A new variational approach optimizes the time-evolution operator and has been demonstrated to outperform the Trotter-Suzuki decomposition.
arxiv.org/abs/2511.15124
arxiv.org/abs/2511.15124
Beyond Trotterization: Variational Product Formulas for Quantum Simulation
We propose a variational alternative to the Trotter-Suzuki decomposition that provides greater control over errors while preserving the unitary structure of time evolution. The variational parameters ...
arxiv.org
November 20, 2025 at 5:06 PM
Standard Trotter-Suzuki decompositions approximate quantum time evolution but can be inaccurate and require many gates. A new variational approach optimizes the time-evolution operator and has been demonstrated to outperform the Trotter-Suzuki decomposition.
arxiv.org/abs/2511.15124
arxiv.org/abs/2511.15124
Ion-trap quantum computers are one of the main platforms. One of their drawbacks is the speed of the logical gates. A new paper demonstrated that micromotion can be beneficial to the design of fast entangling gates (100 ns to a few microseconds).
arxiv.org/abs/2511.15148
arxiv.org/abs/2511.15148
Radial Fast Entangling Gates Under Micromotion in Trapped-Ion Quantum Computers
Micromotion in radio-frequency ion traps is generally considered detrimental for quantum logic gates, and is typically minimized in state-of-the-art experiments. However, as a deterministic effect, it...
arxiv.org
November 20, 2025 at 5:06 PM
Ion-trap quantum computers are one of the main platforms. One of their drawbacks is the speed of the logical gates. A new paper demonstrated that micromotion can be beneficial to the design of fast entangling gates (100 ns to a few microseconds).
arxiv.org/abs/2511.15148
arxiv.org/abs/2511.15148
Quantum advantage is possible only if both magic and entanglement are present. In a new work, the first experimental demonstration of non-local magic in a superconducting Quantum Processing Unit has been achieved.
arxiv.org/abs/2511.15576
arxiv.org/abs/2511.15576
Experimental demonstration of non-local magic in a superconducting quantum processor
Magic is a non-classical resource whose efficient manipulation is fundamental to advancing efficient and scalable fault-tolerant quantum computing. Quantum advantage is possible only if both magic and...
arxiv.org
November 20, 2025 at 5:06 PM
Quantum advantage is possible only if both magic and entanglement are present. In a new work, the first experimental demonstration of non-local magic in a superconducting Quantum Processing Unit has been achieved.
arxiv.org/abs/2511.15576
arxiv.org/abs/2511.15576
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.)
November 19, 2025 at 5:02 PM
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.)
Tile codes are a new type of QEC code that uses a 2D lattice but is potentially more efficient in encoding than surface code. A new paper studies their logical operators and symmetries. This work lays the groundwork for using tile codes in fault-tolerant quantum computer.
arxiv.org/abs/2511.14589
arxiv.org/abs/2511.14589
Logical Operators and Derived Automorphisms of Tile Codes
The recently introduced tile codes are a promising alternative to surface codes, combining two-dimensional locality with higher encoding efficiency. While surface codes are well understood in terms of...
arxiv.org
November 19, 2025 at 5:02 PM
Tile codes are a new type of QEC code that uses a 2D lattice but is potentially more efficient in encoding than surface code. A new paper studies their logical operators and symmetries. This work lays the groundwork for using tile codes in fault-tolerant quantum computer.
arxiv.org/abs/2511.14589
arxiv.org/abs/2511.14589
Training quantum generative models is hard because estimating gradients is experimentally difficult and noisy. Fermionic Born Machines are generative models that can be trained classically but need sampling on a quantum device for inference.
arxiv.org/abs/2511.13844
arxiv.org/abs/2511.13844
Fermionic Born Machines: Classical training of quantum generative models based on Fermion Sampling
Quantum generative learning is a promising application of quantum computers, but faces several trainability challenges, including the difficulty in experimental gradient estimations. For certain struc...
arxiv.org
November 19, 2025 at 5:02 PM
Training quantum generative models is hard because estimating gradients is experimentally difficult and noisy. Fermionic Born Machines are generative models that can be trained classically but need sampling on a quantum device for inference.
arxiv.org/abs/2511.13844
arxiv.org/abs/2511.13844
Entanglement is a major resource for quantum computing. However, detecting it can be challenging, especially for large systems. The authors of a new work present a method to detect entanglement partitions in quantum computers by exploiting their symmetries.
arxiv.org/abs/2511.13822
arxiv.org/abs/2511.13822
Detection of many-body entanglement partitions in a quantum computer
We present a method to detect entanglement partitions of multipartite quantum systems, by exploiting their inherent symmetries. Structures like genuinely multipartite entanglement, $m$-separability an...
arxiv.org
November 19, 2025 at 5:02 PM
Entanglement is a major resource for quantum computing. However, detecting it can be challenging, especially for large systems. The authors of a new work present a method to detect entanglement partitions in quantum computers by exploiting their symmetries.
arxiv.org/abs/2511.13822
arxiv.org/abs/2511.13822
While quantum computing is traditionally focused on discrete-variable systems, the inclusion of continuous-variable modes can offer some advantages. A review discusses the advantages, the applications, and the architecture of hybrid quantum computers.
arxiv.org/abs/2511.13882
arxiv.org/abs/2511.13882
Hybrid continuous-discrete-variable quantum computing: a guide to utility
Quantum computing has traditionally centered around the discrete variable paradigm. A new direction is the inclusion of continuous variable modes and the consideration of a hybrid continuous-discrete ...
arxiv.org
November 19, 2025 at 5:02 PM
While quantum computing is traditionally focused on discrete-variable systems, the inclusion of continuous-variable modes can offer some advantages. A review discusses the advantages, the applications, and the architecture of hybrid quantum computers.
arxiv.org/abs/2511.13882
arxiv.org/abs/2511.13882