661 reputation
46
bio website aholzner.wordpress.com
location
age
visits member for 3 years, 8 months
seen Jul 28 at 20:19

Jul
24
comment What will be the goal of (V)LHC after receiving upgrades?
175-200 TeV will certainly not happen in 2019. The energy limitation of the current LHC comes from the maximum field the dipole (bending) magnets can produce. To go to higher energies, one needs to either dig a longer tunnel or do extensive research & development to build large scale magnets achieving higher magnetic fields or both (this is called FCC-hh, there is also a similar Chinese project). Given the large cost of such a project, studies are currently going on to reduce cost and a decision whether or not to build such a machine will not be taken until we have more results from LHC.
Jun
18
comment What is the symmetry associated with the local particle number conservation law for fluid?
see also the question on the symmetry associated to the conservation of mass here: physics.stackexchange.com/q/2690
Jun
18
comment What is the symmetry which is responsible for conservation of mass?
see also physics.stackexchange.com/questions/24596/… on the discussion of the converse Noether's theorem
Jun
13
comment Uncertainty principle - momentum so precise that uncertainty of position is outside light-cone?
how can we talk about particles for which we are not certain they are somewhere in the universe ?
May
5
comment Distance and time measurement in the famous Superluminal Neutrinos Experiment
see mi.infn.it/~psala/Icarus/nugsweb/cngs_und.jpg on your question 1 ('Ginevra' is where CERN is). The maximum depth of the path is 10km underground... Digging a tunnel of 700km length may technically be possible but is too expensive (not to mention the time it would take to complete...)
Feb
27
comment What will happen if we will be able to produce a quark-gluon plasma and the we cool it down?
yes, the quark gluon plasma also contains antiquarks. Even an ordinary proton contains anti quarks in what is called the 'sea'. These are created when a gluon splits into a quark/anti-quark pair and normally 'recombine' quickly but they can interact with the quarks/gluons/antiquarks of another proton in a collision. So even if no quark gluon plasma is created in a particular proton-proton (or Lead ion-Lead ion) collision, antiparticles (such as antiprotons) can be produced.
Feb
27
comment What will happen if we will be able to produce a quark-gluon plasma and the we cool it down?
yes, the purpose of colliders is to have energies (or better: energy densities) similar to those shortly after the big bang (in the lab) to study the relevant physical processes which led to the formation of the universe we know today.
Feb
27
comment What will happen if we will be able to produce a quark-gluon plasma and the we cool it down?
yes, exactly. Protons and neutrons are baryons (but in principle other baryons could be formed as well but these are typically short lived as are the mesons).
Feb
27
comment Is there any way to annihilate matter without the use of anti-matter?
The experimental lower limit on this decay mode of the proton (see pdg8.lbl.gov/rpp2013v2/pdgLive/… ) is $8.2 \cdot 10^{33}$ years (the corresponding publication is here: inspirehep.net/record/814697 ) . This is $5.9\cdot 10^{23}$ larger than the estimated age of the universe (13.8 billion years).
Feb
19
comment Why does the Sun turn red near sunset?
yes, redshift from Doppler effects are negligible (40'000 km / day is about $1.5 \cdot 10^{-6}$ of the speed of light). If the redshift were responsible for the sunlight turning red in the evening one would expect it to be affected equally by blue shift in the morning...
Feb
19
comment Why does the Sun turn red near sunset?
I've seen many red sunrises. Are you sure you start watching the sun in the morning at the same altitude (height above the horizon) as you experience it red in the evening ? Is the region west of you more dusty than the area east of you (e.g. land on the west, sea on the east) ? Is air pollution in your area stronger in the evening than in the morning ?
Dec
23
comment Possible values of energies and impulses of virtual photon emitted by real electron
if you mean the photon and electron at the time corresponding to the the middle of this graph, there is not a single possible energy for them but there is a range of energies (following a probability distribution).
Nov
20
comment Using gravity to send messages (at the speed of light)
why not using light (or electromagnetic waves in general) to send messages at the speed of light ?! Gravitational wave detectors such as LIGO, LISA and VIRGO are quite large and complicated...
Oct
9
comment What are the strongest sources of collimated neutrons and protons?
interesting project ! But the current seems to be 0.019 mA (so in the lower region of the above diagram) and probably up to 106 keV (i.e. 0.000106 GeV)
Oct
9
comment Spin of a decay product
It's not clear in which case 'spin' means 'spin state' (current angular momentum projection) and which case 'spin' means 'property of a particle' (maximum possible angular momentum projection). Also, consider taking into account the orbit spin of the A,B,C system.
Oct
8
comment What are the strongest sources of collimated neutrons and protons?
A note on the 500mA of beam current of the LHC: these protons make 11'000 revolutions per second. If your experiment would absorb or otherwise destroy the beam, you could only use 1/11'000 of the 500 mA (I found that the highest beam intensities in 2012 were about $229\cdot10^{12}$ protons per beam). On the other hand, whether the beam is bunched or continuous does not affect the (time averaged) current.
Oct
6
comment Chance of objects going against greater entropy?
compare (the inverse of) $10^{-10^{23}}$ or $10^{-10^{19}}$ to the estimated number of atoms in the observable universe (estimated to be $10^{80}$) and you'll realize it is really small...
Oct
6
comment Is it possible for the entropy in an isolated system to decrease?
see e.g. physics.stackexchange.com/a/547/671 for a discussion of how small this 'pure chance' typically is for macroscopic systems... (and compare this to the number of atoms in the observable universe which is estimated to be $10^{80}$)
Sep
25
comment Sharp cut-off, quadratic corrections and naturalness
a theory should be considered valid as long as it does not contradict experimental observations. And in principle, no new physics phenomena beyond the Standard Model may turn up which means we would have to set the cutoff parameter to a value comparable to the Planck scale (which is a 'fine tuning problem'). One way of interpreting the cutoff scale is the scale up to which the Standard Model is valid and at which a new physics phenomena appear (which then can e.g. cancel these divergencies).
Sep
20
comment What are the strongest sources of collimated neutrons and protons?
The sun for example must emit a very high number of protons per second (and I bet there are other sources in the universe), but admittedly these are not very focused...