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#physics

247 posts142 participants17 posts today
Philo Sophies

🚀 Beaming like in Star Trek – just science fiction?

Anton Zeilinger researched quantum entanglement and teleportation – and Gerd Ganteför explains whether this could one day become a reality with “Scotty, beam me up!”

🔬 Quantum physics, the limits of reality, and the great dream of teleportation – what is possible, and what remains fantasy?

📽 More in the Zoomposium interview: youtu.be/V4pUEEtFCUo

#Beaming#QuantumTeleportation#Entanglement
MPI for Gravitational Physics

Almost exactly 15 years ago to the day, we published the first pulsar discovery with our distributed computing project / citizen science project @einsteinathome in the journal “Science”.

ℹ️ aei.mpg.de/219343/einstein-hom (press release)

📄 arxiv.org/abs/1008.2172 (publication on arXiv)

📄 science.org/doi/10.1126/scienc (publication in Science)

#OTD#Throwback#Pulsar
Continued thread
Daniel Pelliccia

Quite surprisingly, most of the properties of (classical) synchrotron radiation were worked out by G.A. Schott in1907--1912 in his dissertation work.

Working in a 'pre-quantum' world, Schott wanted to explain the observed lines in the emission #spectra of atoms. He started with a ‘Rutherford-like' atomic model where point electrons move in closed orbits around a nucleus: what would the emission spectra of such accelerated particles be like?

Starting from these premises, Schott derived the emission spectrum of (what we know today as) synchrotron light!

As we understand today, the motion of bound electrons cannot be explained by classical #Electrodynamics. Schott's formulas didn't work in describing atomic spectra and his work was forgotten for a while, only to be rediscovered in the 1940s when the first synchrotron machines were being built.

Now, electrons moving on macroscopic curved trajectories are extremely well described by classical electrodynamics, and Schott's formulas work exceedingly well in predicting the properties of #synchrotron light.

#physics

3/N

Rxiv cytoskeleton

📰 "Physical Principles of Size and Frequency Scaling of Active Cytoskeletal Spirals"
arxiv.org/abs/2508.10114
#Physics.Bio-Ph #Cond-Mat.Soft #Q-Bio.Bm #Myosin

arXiv logo
arXiv.orgPhysical Principles of Size and Frequency Scaling of Active Cytoskeletal SpiralsCytoskeletal filaments transported by surface immobilized molecular motors with one end pinned to the surface have been observed to spiral in a myosin-driven actin 'gliding assay'. The radius of the spiral was shown to scale with motor density with an exponent of -1/3, while the frequency was theoretically predicted to scale with an exponent of 4/3. While both the spiraling radius and frequency depend on motor density, the theory assumed independence of filament length, and remained to be tested on cytoskeletal systems other than actin-myosin. Here, we reconstitute dynein-driven microtubule spiraling and compare experiments to theory and numerical simulations. We characterize the scaling laws of spiraling MTs and find the radius dependence on force density to be consistent with previous results. Frequency on the other hand scales with force density with an exponent of ~1/3, contrary to previous predictions. We also predict that the spiral radius scales proportionally and the frequency scales inversely with filament length, both with an exponent of ~1/3. A model of variable persistence length best explains the length dependence observed in experiments. Our findings that reconcile theory, simulations, and experiments improve our understanding of the role of cytoskeletal filament elasticity, mechanics of microtubule buckling and motor transport and the physical principles of active filaments.
Rxiv mechanobio

📰 "Towards controlling electron charge with nanoparticle assisted laser wakefield accelerators"
arxiv.org/abs/2508.10685 #Physics.Plasm-Ph #Dynamics #Cell

arXiv logo
arXiv.orgTowards controlling electron charge with nanoparticle assisted laser wakefield acceleratorsThis study explores nanoparticle-assisted electron injection as a method for controlling beam charge in laser wakefield acceleration through particle-in-cell simulations. We systematically investigate how the material (Li through Au) and size (50-200 nm) of nanoparticles influence electron injection dynamics and beam charge. Our results demonstrate that beam charge (10-600 pC) can be effectively controlled by adjusting these parameters. We identify a saturation threshold in the nanoparticle electric field strength, beyond which beam charge depends on the total number of atoms in the nanoparticle rather than on the electron density after ionization. Significant electron injection occurs across multiple plasma wave periods with distribution patterns influenced by nanoparticle properties leading to increased beam charge but a broader energy spread. These findings offer practical guidelines for experimental implementation of nanoparticle-assisted injection in laser wakefield accelerators to tailor electron beam characteristics for various applications.
Rxiv mechanobio

📰 "The Birth of Quantum Mechanics: A Historical Study Through the Canonical Papers"
arxiv.org/abs/2503.13630 #Physics.Hist-Ph #Mechanics #Quant-Ph #Matrix

arXiv logo
arXiv.orgThe Birth of Quantum Mechanics: A Historical Study Through the Canonical PapersThis paper explores the historical development of the theory of quantum mechanics between 1900 and 1927 by chronological examination of the foundational papers and ideas. Beginning with Planck's introduction of energy quantisation in blackbody radiation, we follow the emergence of Einstein's light quanta hypothesis, Bohr's atomic model, and the statistical implications of indistinguishable particles. Special emphasis is placed on the transition from the Old Quantum Theory to modern quantum mechanics, particularly through Heisenberg's matrix mechanics and Schrödinger's wave mechanics. This study aims to provide a structured historical account, offering insights into the conceptual transformations that led to quantum mechanics while making the development accessible to physicists, historians of science, and advanced students interested in the origins of modern quantum theory.
Rxiv mechanobio

📰 "The Algebra of the Pseudo-Observables I: Why Quantum Mechanics is the ultimate description of Reality"
arxiv.org/abs/1707.05633 #Physics.Hist-Ph #Mechanics #Quant-Ph #Matrix

arXiv logo
arXiv.orgThe Algebra of the Pseudo-Observables I: Why Quantum Mechanics is the ultimate description of RealityThis paper is the first of several parts introducing a new powerful algebra: the algebra of the pseudo-observables. This is a C*-algebra whose set is formed by formal expressions involving observables. The algebra is constructed by applying the Occam's razor principle, in order to obtain the minimal description of physical reality. Proceeding in such a manner, every aspect of quantum mechanics acquires a clear physical interpretation or a logical explanation, providing, for instance, in a natural way the reason for the structure of complex algebra and the matrix structure of the formulation of Werner Heisenberg of quantum mechanics. Last but not least, the very general hypotheses assumed, allow one to state that quantum mechanics is the unique minimal description of physical reality.
Rxiv mechanobio

📰 "Physical Principles of Size and Frequency Scaling of Active Cytoskeletal Spirals"
arxiv.org/abs/2508.10114 #Physics.Bio-Ph #Cond-Mat.Soft #Cytoskeletal #Q-Bio.Bm #Force

arXiv logo
arXiv.orgPhysical Principles of Size and Frequency Scaling of Active Cytoskeletal SpiralsCytoskeletal filaments transported by surface immobilized molecular motors with one end pinned to the surface have been observed to spiral in a myosin-driven actin 'gliding assay'. The radius of the spiral was shown to scale with motor density with an exponent of -1/3, while the frequency was theoretically predicted to scale with an exponent of 4/3. While both the spiraling radius and frequency depend on motor density, the theory assumed independence of filament length, and remained to be tested on cytoskeletal systems other than actin-myosin. Here, we reconstitute dynein-driven microtubule spiraling and compare experiments to theory and numerical simulations. We characterize the scaling laws of spiraling MTs and find the radius dependence on force density to be consistent with previous results. Frequency on the other hand scales with force density with an exponent of ~1/3, contrary to previous predictions. We also predict that the spiral radius scales proportionally and the frequency scales inversely with filament length, both with an exponent of ~1/3. A model of variable persistence length best explains the length dependence observed in experiments. Our findings that reconcile theory, simulations, and experiments improve our understanding of the role of cytoskeletal filament elasticity, mechanics of microtubule buckling and motor transport and the physical principles of active filaments.
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