Motion Mountain - The Adventure of Physics, Vol 5 of 6 - Pleasure, Technology and Stars

354 Pages·2011·24.29 MB·English

by  Christoph Schiller

Christoph Schiller
MOTION MOUNTAIN
the adventure of physics – vol.v
pleasure, technology and stars
www.motionmountain.net

ChristophSchiller
Motion Mountain
The Adventure of Physics
Volume V
Pleasure, Technology
and Stars
Edition24.24,available asfreepdfat
www.motionmountain.net
Editiovicesimaquarta.
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quartoannoOlympiadisvicesimaenonae.
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Twenty-fourthedition.
Copyright©2011byChristophSchiller,
thefourthyearofthe29thOlympiad.
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ToBritta,EstherandJustusAaron
τῷἐμοὶδαὶμονι
DieMenschenstärken,dieSachenklären.
PREFACE
“Primummovere,deindedocere.* ”
Antiquity
This book is written for anybody who is curious about nature and motion. Curiosity
M
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abouthowbodies,imagesandemptyspacemoveleadstomanyadventures.Thepresent tio
n
volumepresentsthebestadventuresaboutthemotioninsidepeople,insideanimals,and Mo
u
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insideanytypeofmatter–fromthelargeststarstothesmallestnuclei. tain
Motioninsidebodies–deadoralive–isdescribedbyquantumtheory.Quantumthe- –Th
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oryisthedescriptionofmotionbasedonasmallestaction,orbetter,asmallestchange. A
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Withthisbasicidea,thetextshowshowtodescribelife,deathandpleasure.Thesmallest ntu
changealsoexplainstheobservationsofchemistry,geology,materialscienceandastro- reo
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pinhyFsigicusr.eIn1.tThheesytrfuocrtmuraepopflpiehdysqiucsa,ntthuemseptohpysicicsscaonrrdesapreonpdretsoenthteedthinreteh‘iqsutaenxttu.Thm’epsotionrtys hysics
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grewfromathreefoldaimthatIhavepursuedsince1990:topresentthebasicsofmotion f
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inaInwoarydtehrattoisbseimsimplpel,eu,pthteotdexattefoacnudsecsapotnivcaotinncge.pts,whilekeepingmathematicstothe availab
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necessary minimum. Understanding the concepts of physics is given precedence over free
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usingformulaeincalculations.Thewholetextiswithinthereachofanundergraduate. fch
Inordertobeuptodate,thetextisenrichedbythemanygems–boththeoreticaland arg
e
empirical–thatarescatteredthroughoutthescientificliterature. atw
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Inordertobecaptivating,thetexttriestostartlethereaderasmuchaspossible.Read- w.m
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ing a book on general physics should be like going to a magic show. We watch, we are tio
n
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astonished, we do not believe our eyes, we think, and finally we understand the trick. o
u
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Whenwelookatnature,weoftenhavethesameexperience.Indeed,everypagepresents tain
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atleast onesurprisethatmakesthereaderthink.Andnumerousinterestingchallenges et
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areproposed. o
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Themottoofthetext,dieMenschenstärken,dieSachenklären,afamousstatementby yrig
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HartmutvonHentigonpedagogy,translatesas:‘Tofortifypeople,toclarifythings.’Clar- ©
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ifyingthingsrequirescourage,aschanginghabitsofthoughtproducesfear,oftenhidden risto
p
byanger.Butbyovercomingourfearswegrowinstrength.Andweexperienceintense h
S
ch
and beautifulemotions.Allgreatadventuresin life allow this, and exploringmotion is iller
oneofthem. No
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Munich,24June2011. 19
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*‘Firstmove,thenteach.’Inmodernlanguages,thementionedtypeofmoving(theheart)iscalledmotivat- ne
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ing;bothtermsgobacktothesameLatinroot. 01
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8 preface
PHYSICS: Unified description of motion Why does motion
Describing motion with action. Adventures: understanding occur? What are
motion, intense joy with space, time and
thinking, catching a quantum particles?
glimpse of bliss,
calculating
masses and
couplings.
Quantum
General relativity theory with gravity Quantum field theory
Adventures: the Adventures: bouncing Adventures: building
night sky, measu- neutrons, under- accelerators, under-
ring curved space, standing tree standing quarks, stars,
exploring black growth. bombs and the basis of
holes and the life, matter, radiation. Mo
universe, space How do small tionM
and time. things move? ou
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What are things? tain
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How do The
Classical gravity everyday, Special relativity Quantum theory Adve
Adventures: fast and large Adventures: light, Adventures: death, ntu
climbing, skiing, things move? magnetism, length sexuality, biology, reo
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space travel, contraction, time enjoying art and P
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the wonders of dilation and colours, all high-tech ysics
astronomy and E0 = mc2. business, medicine, pd
geology. chemistry, evolution. ffi
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G c h, e, k availab
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Galilean physics, heat and electricity freeo
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Adventures: sport, music, sailing, cooking, ch
describing beauty and understanding its origin, arge
using electricity and computers, atw
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understanding the brain and people. w
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FIGURE 1 Acompletemapofphysics:theconnectionsaredefinedbythespeedoflightc,the tion
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gravitationalconstantG,thePlanckconstanth,theBoltzmannconstantkandtheelementarychargee. ou
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Inmyexperienceasateacher,therewasonelearningmethodthatneverfailedtotrans- Ch
form unsuccessful pupilsintosuccessful ones: if you readabook for study, summarize ristop
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every section you read, in your own words, aloud. If you are unable to do so, read the Sch
section again. Repeat this until you can clearly summarize what you read in your own iller
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words,aloud.Youcandothisaloneinaroom,orwithfriends,orwhilewalking.Ifyou vem
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dothiswitheverythingyouread,youwillreduceyourlearningandreadingtimesignif- er
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icantly. In addition, you will enjoy learning from good texts much more and hate bad 97
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textsmuchless.Mastersofthemethodcan use itevenwhilelisteningtoalecture,ina Jun
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lowvoice,thusavoidingtoevertakenotes. 01
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preface 9
Using this book
Textingreen,asfoundinmanymarginalnotes,marksalinkthatcanbeclickedinapdf
reader. Such green links are either bibliographic references, footnotes, cross references
tootherpages,challengesolutions,orpointerstowebsites.
Solutionsandhintsforchallengesaregivenintheappendix.Challengesareclassified
as research level (r), difficult (d), standard student level (s) and easy (e). Challenges of
typer,dorsforwhichnosolutionhasyetbeenincludedinthebookaremarked(ny).
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Contents
14 1 Motion for enjoying life
14 Frombiologicalmachinestominiaturization
Reproduction 16 •Quantummachines 16 •Howdowemove?–Molecularmo-
tors 18 •Linearmolecularmotors 19 •Curiositiesandfunchallengesaboutbiol-
ogy 21
27 Thephysicsofpleasure
Thenervesandthebrain 30 •Livingclocks 31 •Whendoclocksexist? 33 •The
precisionofclocks 34 •Whyarepredictionssodifficult,especiallyofthefuture? 35
•Decayandthegoldenrule 36 •Thepresentinquantumtheory 37 •Whycan
weobservemotion? 38 •RestandthequantumZenoeffect 38 •Consciousness–
aresultofthequantumofaction 39 •Whycanweobservemotion?–Again 40
M
•Curiosities and fun challenges about quantum experience 40 •Summary on o
tio
pleasure 43 n
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44 2 Changing the world with quantum theory ntain
44 Chemistry–fromatomstoDNA –
Th
Bonds 45 •Ribonucleicacidanddeoxyribonucleicacid 48 •Curiositiesandfun eA
d
challengesaboutchemistry 48 ve
n
tu
50 Materialsscience re
o
Why does the floor not fall? 50 •Rocks and stones 51 •Some interesting crys- fP
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tals 51 •Howcanwelookthroughmatter? 59 •Whatisnecessarytomakematter ysics
invisible? 61 •Howdoesmatterbehaveatthelowesttemperatures? 62 •Curiosi- p
d
f
tiesandfunchallengesaboutmaterialsscience 62 file
68 QuManottuiomntwecithhnooultofgryiction–superconductivityandsuperfluidity 69 •Thefractional available
quantum Hall effect 70 •Lasers and other spin-one vector boson launchers 71 free
o
•Cantwophotonsinterfere? 77 •Cantwoelectronbeamsinterfere? 78 •Chal- fch
lenges,dreamsandcuriositiesaboutquantumtechnology 78 arg
e
at
81 3 Quantum electrodynamics – the origin of virtual reality w
w
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Ships, mirrors and the Casimir effect 81 •The Lamb shift 83 •The QED La- .m
o
grangiananditssymmetries 84 •Interactionsandvirtualparticles 85 •Vacuum tio
n
m
energy:infiniteorzero? 86 •Movingmirrors 86 •Photonshittingphotons 87 ou
n
•Isthevacuumabath? 88 •Renormalization–whyisanelectronsolight? 88 tain
.n
•Curiositiesandfunchallengesofquantumelectrodynamics 89 •Howcanone et
moveonperfectice?–Theultimatephysicstest 93 •Asummaryofquantumelec- Co
p
trodynamics 94 •OpenquestionsinQED 96 yrig
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98 4 Quantum mechanics with gravitation – a first approach C
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Falling atoms 98 •Playing table tennis with neutrons 98 •The gravitational risto
p
phaseofwavefunctions 99 •ThegravitationalBohratom 100 •Gravitationand hS
ch
limits to disorder 101 •Measuring acceleration with a thermometer: Fulling– iller
Davies–Unruhradiation 102 •Blackholesaren’tblack 103 •Thelifetimeofblack No
holes 106 •Blackholesareallovertheplace 106 •Gammaraybursts 107 •Ma- vem
b
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terial properties of black holes 109 •How do black holes evaporate? 110 •The r1
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informationparadoxofblackholes 111 •Moreparadoxes 112 •Curiositiesabout 7–
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quantum theoryandgravity 113 •Quantum mechanics of gravitation 114 •Do ne
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gravitons exist? 114 •Space-time foam 115 •Decoherence of space-time 115 • 01
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