Duda Jarek
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Immunity by incompatibility – hope in chiral life
Duda Jarek replied to Duda Jarek's topic in Biology
I don't doubt that freecell synthesis can get high production ... assuming you have a good source of e.g. polymerase, which are the real problem here  without mirror cells and ribosomes ... Beside industrial applications, mirror life will be also a crucial milestone in development of synthetic life  the first really different and reasonable (in contrast to e.g. additional nucleotides), and natural development will make it in reach in a few decades, e.g.: 2002  synthetic virus: https://en.wikipedia.org/wiki/Synthetic_virology 2010  synthetic cell: https://en.wikipedia.org/wiki/Artificial_cell#Synthetic_cells 2013  synthetic ribosome: https://en.wikipedia.org/wiki/Synthetic_ribosome 2016  large mirror protein (polymerase) Will we be really able to contain it then forever?  with human factors, antibiotics resistance, accidents, etc. ... it seems a matter of time when it will finally reach natural environment and start searching an ecological niche to populate, evolve, diversify ... 
Immunity by incompatibility – hope in chiral life
Duda Jarek replied to Duda Jarek's topic in Biology
I don't have education in biochemistry (physics, cs, math), but it seems highly unlikely that you could produce macroscopic (e.g. grams) amounts of large molecules this way (?) Especially proteins requiring mirror ribosomes, often complex post processing, help in folding ... Cellfree synthesis might be useful for extremely rare diseases, but finding some promising drug for a common disease in this huge mirror world, there would be needed kilograms, tonnes to synthesize  what is completely unrealistic without mirror life ... which should become easier every year due to natural development of technology. Anyway, I think it is a matter of time (less than a century) when, due to ambition/money incentives/"because we can", somebody will open this Pandora box, e.g. secretly in a lab in China like for CRISPR babies ... 
Immunity by incompatibility – hope in chiral life
Duda Jarek replied to Duda Jarek's topic in Biology
Hello, the Nature article mentions aptamers as direct application, which are length 3080 oligonucleotides. Enantiomers of the small ones probably can be directly synthesized in negligible quantity. Now they have mirror polymerase allowing to speed it up, but being relatively costly to synthesize, how many copies can produce a single molecule of polymerase? For mass production there is needed mirror life. And aptamers are just the beginning  mirror life would literally double the space of possible large molecules we can mass produce. Starting actively searching this space, we can find many valuable ones. Especially enzymes  complex and effective nanomachines, optimized for very sophisticated tasks. Anyway, there are extremely strong incentives, not only financial, to go toward finally synthesizing mirror life  like CRISPR babies, there might be no way to stop it (?) What we can do is trying to prepare  understand it well, try to protect from the dangers. And there are many of them  earlier than mirror cyanobacteria dominating our ecosystem due to less prepare natural enemies, potentially killing us all in a few centuries. Bacteria has extremely fast evolution  already can consume lsugars, and can quickly adapt to others. Mirror E. Coli might already find unusual ecological niches, disturbing ecosystem in an unpredictable way. I wouldn't be surprised if synthesizing mirror life was a factor in Fermi paradox  it is a natural possibility in development of civilization ... which might lead to its extermination. 
Experimental boundaries for size of electron?
Duda Jarek replied to Duda Jarek's topic in Modern and Theoretical Physics
studiot, according to Wikipedia, Earnshaw's theorem says "that a collection of point charges cannot be maintained in a stable stationary equilibrium configuration solely by the electrostatic interaction of the charges" ... while here we are talking about configuration of EM field of a single electron. Regarding " Or are you claiming that non tunneling electrons do not have a wavefunction that extends beyond their situs? "  no, by "on average" I mean that you can translate this wavefunction into probability to answer the question of size of electron, e.g. a radius such that half of 511keVs energy is on average in this radius around the center of electron. swansont, if you want to relate radius of electron to its electric dipole moment ... why not to use magnetic dipole instead?  which is huge. If you are able to defend Dehmelt's gfactor argument I would be really interested. It looks like at first he extrapolated with line, getting negative radius for electron  so he has chosen parabola to get exactly 0 radius for g=2, what is "proving" by assuming the thesis. Also, we have more 3parton particles, like neutron, which RMS radius is negative due to minuses being further than pluses ... For fundamental particles we cannot talk about RMS radius, but we can about differences from (infinite energy) EM field configuration of perfect point charge. 
Experimental boundaries for size of electron?
Duda Jarek replied to Duda Jarek's topic in Modern and Theoretical Physics
As written, I have returned to this topic due to Neumaier's page with many materials: https://www.mat.univie.ac.at/~neum/physfaq/topics/pointlike.html But generally the fundamental question of size of electron remains unanswered  while there are many suggestions of femtometerscale size of electron (as deformation from perfect point charge), I still haven't seen any real (not fitting parabola to two point) arguments that it is essentially smaller (claimed e.g. in Wikipedia). 
Experimental boundaries for size of electron?
Duda Jarek replied to Duda Jarek's topic in Modern and Theoretical Physics
studiot, quantum formalism can be translated into probabilities with Born rule  while we cannot ask about exact e.g. position, QM still allows to ask about its expected value: "on average". swansont, looking at electronpositon scattering cross section as one of suggestions, it includes all their interactions. Electron's 511keV energy is at least partially distributed into energy of fields of interactions: probably mainly EM. Still we don't know this distribution (even average), naive assumption of perfect point would mean infinite energy. So what is this configuration of EM field near the center of electron? E.g. in ball of what radius there is half of this energy? (on average) 
Experimental boundaries for size of electron?
Duda Jarek replied to Duda Jarek's topic in Modern and Theoretical Physics
Ok, you can say that there are some quantum or statistical fluctuations ... I can respond with just adding "on average". For example: ball of which radius contains on average half of 511keVs energy of electron? Is it femtomerscale radius, or much smaller? 
Experimental boundaries for size of electron?
Duda Jarek replied to Duda Jarek's topic in Modern and Theoretical Physics
Generally, we are interested in size of rest electron, not of squeezed electron. There are some complex dependencies from its squeezing with Lorentz contraction  we need to remove them, e.g. by extrapolating to rest energy (any other ways?) A general question regards distribution of electron's 511keVs energy  some of it is in energy of electric field (... infinite assuming perfect point), some could be e.g. in energy of fields related to other interactions electron takes part: gravitational, weak ... So e.g. ball of which radius contains half of 511keVs energy of electron? Is it femtomerscale radius, or much smaller? 
Experimental boundaries for size of electron?
Duda Jarek replied to Duda Jarek's topic in Modern and Theoretical Physics
Arnold Neumaier has responded on stack ( https://physics.stackexchange.com/questions/397022/experimentalboundariesforsizeofelectron )  he has gathered many materials on this topic: https://www.mat.univie.ac.at/~neum/physfaq/topics/pointlike.html But still no clear argument that electron is much smaller then femtometer (?) Anyway, to better specify the problem, define E(r) as energy in a radius r ball around electron. We know that E(r) ~ 511keVs for large r, for smaller it reduces e.g. by energy of electric field. Assuming perfect point charge, we would get E(r) > infinity for r>0 this way. Where does divergence from this assumption starts? More specifically: for example where is maximum of E'(r)  in which distance there is maximal deposition of 511keVs energy? Or median range: such that E(r) = 511/2 keVs. It is not a question about the exact values, only their scale: ~femtometer or much lower? 
How quantum is waveparticle duality of Couder's walking droplets?
Duda Jarek replied to Duda Jarek's topic in Physics
Sure, it misses a lot from real physics, like it seems impossible to model 3D this way, also clock here is external while in physics it is rather internal of particles (de Broglie's, zitterbewegung): https://physics.stackexchange.com/questions/386715/doeselectronhavesomeintrinsic1021hzoscillationsdebrogliesclock But these hydrodynamical analogues provide very valuable intuitions about the real physics ... 
How quantum is waveparticle duality of Couder's walking droplets?
Duda Jarek replied to Duda Jarek's topic in Physics
Oh, muuuch more has happened  see my slides with links to materials: https://www.dropbox.com/s/kxvvhj0cnl1iqxr/Couder.pdf Interference in particle statistics of doubleslit experiment (PRL 2006)  corpuscle travels one path, but its "pilot wave" travels all paths  affecting trajectory of corpuscle (measured by detectors). Unpredictable tunneling (PRL 2009) due to complicated state of the field ("memory"), depending on the history  they observe exponential drop of probability to cross a barrier with its width. Landau orbit quantization (PNAS 2010)  using rotation and Coriolis force as analog of magnetic field and Lorentz force (Michael Berry 1980). The intuition is that the clock has to find a resonance with the field to make it a standing wave (e.g. described by Schrödinger's equation). Zeemanlike level splitting (PRL 2012)  quantized orbits split proportionally to applied rotation speed (with sign). Double quantization in harmonic potential (Nature 2014)  of separately both radius (instead of standard: energy) and angular momentum. E.g. n=2 state switches between m=2 oval and m=0 lemniscate of 0 angular momentum. Recreating eigenstate form statistics of a walker's trajectories (PRE 2013). In the slides there are also hydrodynamical analogous of Casimir and AharonovBohm. 
Duda Jarek started following How physics can violate Pr(A=B) + Pr(A=C) + Pr(B=C) >= 1 ?

How physics can violate Pr(A=B) + Pr(A=C) + Pr(B=C) >= 1 ?
Duda Jarek posted a topic in Modern and Theoretical Physics
While the original Bell inequality might leave some hope for violation, here is one which seems completely impossible to violate  for three binary variables A,B,C: Pr(A=B) + Pr(A=C) + Pr(B=C) >= 1 It has obvious intuitive proof: drawing three coins, at least two of them need to give the same value. Alternatively, choosing any probability distribution pABC among these 2^3=8 possibilities, we have: Pr(A=B) = p000 + p001 + p110 + p111 ... Pr(A=B) + Pr(A=C) + Pr(B=C) = 1 + 2 p000 + 2 p111 ... however, it is violated in QM, see e.g. page 9 here: http://www.theory.caltech.edu/people/preskill/ph229/notes/chap4.pdf If we want to understand why our physics violates Bell inequalities, the above one seems the best to work on as the simplest and having absolutely obvious proof. QM uses Born rules for this violation: 1) Intuitively: probability of union of disjoint events is sum of their probabilities: pAB? = pAB0 + pAB1, leading to above inequality. 2) Born rule: probability of union of disjoint events is proportional to square of sum of their amplitudes: pAB? ~ (psiAB0 + psiAB1)^2 Such Born rule allows to violate this inequality to 3/5 < 1 by using psi000=psi111=0, psi001=psi010=psi011=psi100=psi101=psi110 > 0. We get such Born rule if considering ensemble of trajectories: that proper statistical physics shouldn't see particles as just points, but rather as their trajectories to consider e.g. Boltzmann ensemble  it is in Feynman's Euclidean path integrals or its thermodynamical analogue: MERW (Maximal Entropy Random Walk: https://en.wikipedia.org/wiki/Maximal_entropy_random_walk ). For example looking at [0,1] infinite potential well, standard random walk predicts rho=1 uniform probability density, while QM and uniform ensemble of trajectories predict different rho~sin^2 with localization, and the square like in Born rules has clear interpretation: Is ensemble of trajectories the proper way to understand violation of this obvious inequality? Comparing with local realism from Bell theorem, path ensemble has realism and is nonlocal in standard "evolving 3D" way of thinking ... however, it is local in 4D view: spacetime, Einstein's block universe  where particles are their trajectories. What other models with realism allow to violate this inequality? 1 reply

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Experimental boundaries for size of electron?
Duda Jarek replied to Duda Jarek's topic in Modern and Theoretical Physics
Sure, it isn't  fm size is only a suggestion, but a general conclusion here is that cross section does not offer a subfemtometer boundary for electron size (?) Dehmelt's argument of fitting parabola to 2 points: so that the third point is 0 for g=2 ... is "proof" of tiny electron radius by assuming the thesis ... and at most criticizes electron built of 3 smaller fermions. So what experimental evidence bounding size of electron do we have? 
Experimental boundaries for size of electron?
Duda Jarek replied to Duda Jarek's topic in Modern and Theoretical Physics
Sure, so here is the original Cabbibo electropositron collision 1961 paper: https://journals.aps.org/pr/abstract/10.1103/PhysRev.124.1577 Its formula (10) says sigma ~ \beta/E^2 ... which extrapolation to resting electron gives ~ 2fm radius. Indeed it would be great to understand corrections to potential used in Schrodinger/Dirac, especially for r~0 situations like electron capture (by nucleus), internal conversion or positronium. Standard potential V ~ 1/r goes to infinity there, to get finite electric field we need to deform it in femtometer scale 
Experimental boundaries for size of electron?
Duda Jarek replied to Duda Jarek's topic in Modern and Theoretical Physics
Could you give some number? Article? We can naively interpret crosssection as area of particle, but the question is: crosssection for which energy should we use for this purpose? Naive extrapolation to resting electron (not Lorentz contracted) suggests ~2fm electron radius this way (which agrees with size of needed deformation of electric field not to exceed 511 keVs energy). Could you propose some different extrapolation?