Rxiv mechanobio2d ago
📰 "Cyclic ladder operators and hidden Weyl-Heisenberg structure in a Floquet system"
https://arxiv.org/abs/2606.06810 #Physics.Optics #Dynamics #Quant-Ph #Matrix
Cyclic ladder operators and hidden Weyl-Heisenberg structure in a Floquet system

Ladder operators, found in the quantum harmonic oscillator and other quantized systems, provide an elegant approach to solving or understanding otherwise intricate physics problems. In this Letter, we discuss cyclic ladder operators in both Hermitian and non-Hermitian systems with a finite Hilbert space, with the highest (lowest) level directly descending (ascending) to the lowest (highest) level via a single raising (lowering) operation. We show that an equally spaced energy ladder emerges when these systems have an underlying Weyl-Heisenberg commutation relation, with the cyclic ladder operators and the temporal evolution operator behaving as the generators of the Weyl-Heisenberg group. We further illustrate such a system using a one-dimensional Floquet lattice, where the cyclic ladder operators become diagonal and the temporal evolution simplifies to a permutation matrix after a Floquet period. Our findings reveal a hidden relation between non-trivial dynamics and algebraic principles in Floquet systems, which may exist for other quantum numbers as well besides the energy levels.

arXiv.org
Rxiv mechanobio2d ago
📰 "Complex-gauge control of anomalous Floquet corner responses in a non-Hermitian physical-synthetic photonic lattice"
https://arxiv.org/abs/2606.07038 #Physics.Optics #Dynamics #Quant-Ph #Matrix
Complex-gauge control of anomalous Floquet corner responses in a non-Hermitian physical-synthetic photonic lattice

We propose a non-Hermitian Floquet photonic lattice formed by a physical resonator coordinate and a synthetic frequency coordinate. A two-step modulation protocol realizes a chiral walk in this physical-synthetic plane, with a real synthetic flux controlling loop interference and imaginary gauge fields controlling non-reciprocal envelopes. We show that anomalous corner pairs at quasienergies zero and \(π/T\) exhibit three distinct layers of physics. A non-Bloch higher-order construction predicts whether the \(0/π\) corner pair exists under open boundaries. The imaginary gauge fields select where the right eigenmodes accumulate. The real flux controls the local interference matrix element that determines whether the doubled-period optical response is visible. As a result, the same topological coexistence sector can be bright, skin-dark, or flux-dark in a local optical measurement. We further show that the complex gauge can tune an exceptional point of the two-period corner propagator. At this point the anomalous response keeps its doubled-period sign alternation, but its envelope becomes algebraic because of a Jordan block. These results provide a photonic route to separate topological existence, skin-selected localization, optical visibility, and defective two-period dynamics in a non-Hermitian synthetic dimension.

arXiv.org
Some Bits: Nelson's Linkblog4d ago
Unsloth Gemma 4 QAT: Some deep-in-the-weeds details about boiling down an LLM to a small size you can run on a single desktop computer (or phone)
https://unsloth.ai/docs/models/gemma-4/qat
#unsloth #google #quant #llm #ai #+
Gemma 4 QAT | Unsloth Documentation

Run Google Gemma 4 QAT models locally, including E2B, E4B, 12B, 26B-A4B, and 31B.

Rxiv mechanobio6d ago
📰 "Polalrized reservoirs in dynamics of polariton condensation"
https://arxiv.org/abs/2606.04808 #Physics.Optics #Quant-Ph #Dynamics #Matrix
Polalrized reservoirs in dynamics of polariton condensation

We review the problem of description of the dynamics of driven-disspipative spinor polariton condensates, focusing on the terms corresponding to the coupling between a macroscopic wavefunction of the condensdate and incoherent excitonic reservoir created by a non-resonant pump. We demonstrate that the existing version of the theory breaks down in case, when reservoir has non-zero components of the Stokes vector corresponding to in-plane linear polarization. The polarization invariant theory of reservoir to condensate coupling is formulated with use of the spin density matrix formalism.

arXiv.org
Show thread𝕂𝚞𝚋𝚒𝚔ℙ𝚒𝚡𝚎𝚕6d ago

🧵 …langsam, ja langsam, kommt der EU in den Sinn Google & Co in Frage zu stellen. Ich und viele andere "Nerds" schon vor über 3½ Jahern (siehe oben).

«Digitale Souveränität — EU-Parlament verabschiedet sich von Google als Standard-Suchmaschine:
Stattdessen soll das europäische Qwant zum Einsatz kommen. Parallel dazu treibt die KI-Flut auch der Google-Alternative DuckDuckGo immer mehr User zu»

🕵️ https://www.derstandard.at/story/3000000323303/eu-parlament-verabschiedet-sich-von-google-als-standard-suchmaschine

#suchmaschine #euparlament #digital #quant #duckduckgo #ai #ki #suveranitet

EU-Parlament verabschiedet sich von Google als Standard-Suchmaschine

Stattdessen soll das europäische Qwant zum Einsatz kommen. Parallel dazu treibt die KI-Flut auch der Google-Alternative DuckDuckGo immer mehr User zu

DER STANDARD
Rxiv mechanobioJun 1
📰 "Preventing the Breakdown of Tight-Binding Waveguide Optics by L\"owdin Orthogonalization"
https://arxiv.org/abs/2605.31074 #Physics.Optics #Dynamics #Quant-Ph #Matrix
Preventing the Breakdown of Tight-Binding Waveguide Optics by Löwdin Orthogonalization

Many advancements in optics have relied on the tight-binding approximation, which simplifies the description and prediction of complex system behaviors. This approximation describes the dynamics of the total light field by examining the coupling between the guided modes of individual single-mode substructures -- also known as coupled mode theory. However, the underlying assumption, that the guided modes of individual waveguides form an orthogonal basis, breaks down when waveguides are brought into close proximity or when larger arrays are considered. In this work, we systematically analyze the consequences of this non-orthogonality and show that it leads to a generalized eigenvalue problem involving an overlap matrix, causing a fundamental mismatch between the standard TB model and solutions of the paraxial wave equation. To resolve this issue, we introduce a modified TB framework based on the Löwdin orthogonalization, which constructs an orthonormal basis from the non-orthogonal guided modes while minimally altering their physical shape and preserving their symmetry properties. The resulting Löwdin-TB method restores the standard eigenvalue problem and yields excellent agreement with exact beam propagation simulations across a wide range of system sizes and waveguide separations. Furthermore, it captures important physical effects, such as enhanced long-range coupling and nontrivial hopping phases, that are absent in the standard approach.

arXiv.org
Rxiv mechanobioMay 28
📰 "A Demonstration of Quantum Circuit Implementation for Obstacle Flow Using Carleman-Linearized Lattice Boltzmann Method"
https://arxiv.org/abs/2605.28135 #Physics.Flu-Dyn #Dynamics #Quant-Ph #Matrix
A Demonstration of Quantum Circuit Implementation for Obstacle Flow Using Carleman-Linearized Lattice Boltzmann Method

Fluid simulations, especially at high Reynolds numbers, are computationally expensive on classical computers, making them promising application targets for quantum computing. Recent studies have combined the lattice Boltzmann method (LBM) with Carleman linearization to design quantum algorithms for computational fluid dynamics (CFD). However, practical quantum-circuit implementations of these algorithms that incorporate non-periodic boundary conditions have not been fully explored. In this work, we implement a quantum algorithm for two-dimensional linearized fluid flow around an obstacle, using block-encoding of the linear-system matrix and quantum singular value transformation (QSVT) to solve it. Inflow, outflow, and no-slip boundary conditions are formulated as sparse matrix operations and efficiently embedded into quantum circuits using index-value encoding. We demonstrate logarithmic scaling of the required numbers of qubits and gates with respect to the number of lattice points, suggesting the potential feasibility of quantum-computational fluid dynamics simulations.

arXiv.org
Marius (windsheep)May 26

I think an MBA in quantitative finance was worth the 2 years (2024-2026). Getting back into mathematics. And applying it to management.

I still wait for one high-quality Quant AI or strategic / professional management AI concept.
So far it’s all on a coin-flipping level. Or junior manager. If you have the skills, you see that AI cannot make financial or management decisions.

I don’t see the unique strategic long-term value proposition of US AI. China is getting its own full vertical, from power to tokens. US sanctions have backfired.

Therefore, I think learning Chinese is an equally valuable time investment (to an MBA) that won’t become obsolete due to AI. On the contrary. Chinese will be as relevant for tech work as English.

#mba #chinese #management #quant

Bad Neural NetworkMay 23
https://www.donna-anna.org/de/quant.html Das metaphysische Quant ist eine elemantare, nicht teilbare Einheit, die nichts anderes als eine lokale Anregung der interferierenden Subgraviton-Felder darstellt. #Quant #Teilchen #Einheit #Physik #Metaphysik #Lexikon
Rxiv mechanobioMay 22
📰 "Reduced Dynamical Maps in Finite Temperature Vibronic Coupling Models via Choi Matrices: Numerical Methods and Applications"
https://arxiv.org/abs/2605.22459 #Physics.Chem-Ph #Dynamics #Quant-Ph #Matrix
Reduced Dynamical Maps in Finite Temperature Vibronic Coupling Models via Choi Matrices: Numerical Methods and Applications

We present a streamlined implementation of a computational framework for constructing and analyzing reduced dynamical maps for complex system--bath models at finite temperature. The methodology is based on three established ingredients of quantum dynamics: the Choi--Jamiołkowski isomorphism for the representation of quantum channels, thermofield (TFD) purification of thermal environments, and tensor-train (TT) propagation of the resulting enlarged pure state. The reduced map is obtained from a single unitary propagation in a thermofield-doubled Hilbert space and represented in matrix form through the Choi--Jamiołkowski isomorphism. The TFD evolution is implemented in the TT representation, enabling efficient propagation of high-dimensional purified thermal states. We illustrate the methodology for exciton transfer in the Fenna--Matthews--Olson complex with site-dependent structured spectral densities represented by discretized bosonic environments. The resulting maps are used to analyze decoherence, relaxation, and finite-memory effects, and to assess the crossover to an effectively time-local description. The proposed approach provides a route to compute reduced propagators and to post-process them into memory kernels, transfer tensors, and effective kinetic rate descriptions for complex molecular systems.

arXiv.org