the mystery of matter: the course -...

Peter Paul 09/1/05 PHY313-CEI544 Fall-05 1

PHY313 - CEI544The Mystery of Matter

From Quarks to the CosmosFall 2005

Peter PaulOffice Physics D-143

www.physics.sunysb.eduthen click on PHY313 or CEI544

http://www.physics.sunysb.edu/

The Mystery of Matter: The Course

• The Goal: To understand at a conceptual level…

• the current knowledge about the origin and forms of matter,

• the basic building blocks of nature and what holds them together.

• the appearance of matter in the Universe and its evolution.

• the open issues and the plans to resolve them: The big facilities

• the spin-offs and benefits to society derived from the quest to understand “Matter”.



Is Science incomprehensible, except to scientists ?

• Example: Music is based on strict laws of harmony that govern composition, just like science is based on strict laws.

• Few people, except the trained experts understand these laws.

• But all people can tell whether music is harmonious or not, and can enjoy its beauty.

• Similarly, everybody can appreciate the beauty of the laws of physics, without needing details

The answer is emphatically NO


Can we afford to have “Two Languages”? • A car needs to stop rapidly. The

deceleration is a.• The scientist sees a force F that

wants to smash the driver (mass m) into the windshield.

• Newton's law: • From the law we learn that it is

the deceleration, not the speedthat determines the force.

• Thus use of a seatbelt is important even at low car velocity to counteract this force.

• The non-scientist can understand this and that is important for him/her, if we use the language by which we all communicate.

amF ⋅=

Racing car or land yacht: It’s the deceleration that counts for the seat belts.


Can Nature be dissected and explained by its parts?• Model of a proton: Contains 3 quarks

• Structure of a Ribosome:• It contains 50 different proteins • 3 Transfer RNA’s

(red, blue and green)• It contains billions of protons

• Can we compute the Ribosome structure if we understand the proton? Probably NOT


The Process

The Course will..• be web based: Here is how to go to the web page:http://www.physics.sunysb.eduAll lecture notes will be posted on the web site after the

lecture• There will be 6 homework problems each week, due the

next week, based strictly on material covered each week. The grade will be based on that homework with an optional final for extra credit

• Answer the home work in brief words. Do not copy the lecture notes

• There will be a site visit to BNL for extra credit during one of the lecture periods

http://www.physics.sunysb.edu/


Visit to BNL on November 3, 2005

• The Goal: To visit the RHIC accelerator and its two large detectors, STAR & PHENIX

• The relativistic heavy ion collider uses heavy ion collisions to recreate the universe as it existed ~ 1 µs after the Big Bang

• The tour buses(free) will start here at the beginning of the class and will return by the end of the class.

• Participation will be optional with extra credit for attendance

• Registration two weeks before.see http://www.bnl.gov/rhic/

The STAR Detector at RHIC

http://www.bnl.gov/rhic/


Brookhaven National Laboratory


The View in 1898: Physics is complete

THEN CAME THE REVOLUTION


The State of Physics at the End of 1900

• Newton “invents” mechanics• Maxwell completes electrodynamics

– Light is just an EM wave– Incorporates Optics into EM

• Helmholtz & Boltzmann• complete thermodynamics

• Then Planck discovers energy quantization

• Einstein “sees” the connections between these fields, before Quantum mechanics was developed.

MECHANICS

THERMO-DYNAMICS

ELECTRO-DYNAMICS

OPTICS

ENERGYQUANTIZATION


1905: The Year of Albert Einstein• http://www.aip.org/history/einstein/• In 1905 Einstein produced 3 break-through

papers:1. Photoelectric effect: Light is an energy

quantum that can be treated like a particle. E = h ν

2. Brownian motion: heat is kinetic energy of small particles moving in a medium:

3. Special Relativity: The speed of light must be the same in all inertial reference frame: E = mc2

4. His Gedanken Experiments established a whole new way to gain physical insight

http://www.aip.org/history/einstein/


It all started with Roentgen

• He showed that we could “see” things with detectors other than our human eyes.


The Discovery of Radioactivity

Henri Becquerel: (Accidental) Discovery of Radioactivity from uranium in 1896: Nobel Prize in 1903

http://nobelprize.org/physics/laureates/1903/index.html

http://nobelprize.org/physics/laureates/1903/index.html


The Details of Radioactive Decay law

• Marie and Pierre Curie• Nobel prize in 1903

• No knowledge of Nuclei yet!!• Radioactivity decreases exponentially with

time• Half life: The time it takes for half of the

original radioactivity to decay.• That means that any radioactivity initially

present is never completely “dead”: Quite different from people’s life.

• Each radioactive element has its own characteristic half life.


Electromagnetic Waves demonstrated

•Heinrich Hertz demonstrated in 1885 to 1890 that Electromagnetic Waves could be produced and traveled with the speed of light → 3 x 1010 m/s

•This was the beginning of the communication revolution

•The EM waves had been predicted in 1884 by James Maxwell


Electromagnetic waves and length scales

• Electromagnetic waves have a wave length that ranges over many orders of magnitude.

http://www.colorado.edu/physics/2000/waves_particles/http://www.ngsir.netfirms.com/englishhtm/TwaveA.htm

• The longest distances are usually expressed in light-years. This is the distance that a flash of light would travel in one year. The speed of light is very fast:

• This is a very large distance. Calculate it as part of the Homework.

skmsmc /000,300/10988.2 8 ≈⋅=

http://www.colorado.edu/physics/2000/waves_particles/

http://www.ngsir.netfirms.com/englishhtm/TwaveA.htm


Max Planck then made the big step

His analysis of electromagnetic waves trapped in a cavity led to the conjecture that Energy was quantized, i.e. came in chunks.

This was a phenomenal abstraction because it could not be observed directly! To our eyes light does not seem to come in little flashes.

This is because the Planck energy quantum is a very small chunk.

1 W of visible light contains 1.6 1019

quanta each second!

One quantum of visible light is


The Scales of Physics

Modern physics aims to connect the smallest and the largest objects, the proton and the structures in the Universe.

This means in clear English that the scales and times of our daily experience are not adequate to understand science


The Nomenclature of Dimensions

• Prefixes that define powers of ten

Fraction Prefix Symbol10E(-18) atto a10E(-15) femto f10E(-12) pico p10E(-9) nano n10E(-6) micro µ

10E(-3) milli m1

Multiple Prefix Symbol10E(3) kilo k

10E(6) Mega M

10E(9) Giga G

10E(12) Tera T

10E(15) Peta P

10E(18) Exa E


The Scales of Nature

• http://www.falstad.com/scale/• http://imartinez.etsin.upm.es/ot1/Scale

s.html

• The Planck Scales as the ultimate for our current theory in the Universe:

• TPl = (G h/c5)1/2

Planck Length = 1.6 x 10-33 cmPlanck Time = 5.4 x 10 -44 sPlanck Energy = 1.2 x 10 19 GeV

• G = gravitational constant6.67 x 10-11 N m2/kg2

http://www.falstad.com/scale/

http://imartinez.etsin.upm.es/ot1/Scales.html

http://imartinez.etsin.upm.es/ot1/Scales.html


Red blood cells(~7-8 µm)

DNA~2-1/2 nm diameter

Things NaturalThings Natural Things ManmadeThings ManmadeHead of a pin

1-2 mm

Fly ash~ 10-20 µm

Atoms of siliconspacing ~tenths of nm

Quantum corral of 48 iron atoms on copper surfacepositioned one at a time with an STM tip

Corral diameter 14 nm

Human hair~ 60-120 µm wide

Ant~ 5 mm

Dust mite

200 µm

ATP synthesis

~10 nm diameterNanotube electrode

Carbon nanotube~1.3 nm diameter

O O

O

OO

O OO O OO OO

O

S

O

S

O

S

O

S

O

S

O

S

O

S

O

S

PO

O

The Challenge

Fabricate and combine nanoscale building blocks to make useful devices, e.g., a photosynthetic reaction center with integral semiconductor storage.

Mic

row

orl

d

0.1 nm

1 nanometer (nm)

0.01 µm10 nm

0.1 µm100 nm

1 micrometer (µm)

0.01 mm10 µm

0.1 mm100 µm

1 millimeter (mm)

1 cm10 mm

10-2 m

10-3 m

10-4 m

10-5 m

10-6 m

10-7 m

10-8 m

10-9 m

10-10 m

Visib

le

Nan

owor

ld

1,000 nanometers = In

frare

dUl

travio

letMi

crow

ave

Soft

x-ra

y

1,000,000 nanometers =

The Scale of Things The Scale of Things

Zone plate x-ray “lens”Outer ring spacing ~35 nm

–– Nanometers and MoreNanometers and More

MicroElectroMechanical (MEMS) devices10 -100 µm wide

Red blood cellsPollen grain

Carbon buckyball

~1 nm diameter

Self-assembled,Nature-inspired structureMany 10s of nm

Office of Basic Energy SciencesOffice of Science, U.S. DOE

Version 01-18-05, pmd


Planck’s Constant h

• Relativity becomes important when velocity ~ c

• Quantum effects become important when

energy x size ~ h c

• Example from chip design:Energy scale ~ 3 eVSize ~ 1240/3 nm = 400 nm

This is a very practical dimension!

• The two most important constants in Nature are:

• The speed of light cC = 2.998 x 108 m/s

• Planck’s constant hh = 6.626 x 10-34 J s or

4.137 x 10-15 eV s• h is a very small amount of

“action”

h c = 1240 eV nm


The Energy Scale of Matter

• http://www.jca.umbc.edu/~george/html/courses/glossary/key_energies.html

• Energy units in the standard system is the Joule, 1 W = 1 J/s

• In advanced physics the energy unit is the eV, the energy it takes to accelerate one electric charge with a potential of 1 Volt.

• This unit is very small1 eV = 1.6 10 -19 Joules1000 eV = 1 keV1 Million eV = 1 MeV1 Billion eV = 1 GeV

• A 27-in TV accelerates electrons to 30 keV

,

The Relativistic Heavy Ion Collider accelerates Au ions to 100 GeV x 197 ~ 20 TeV

about 1 Billion times your TV

http://www.jca.umbc.edu/~george/html/courses/glossary/key_energies.html

http://www.jca.umbc.edu/~george/html/courses/glossary/key_energies.html


Energy scale of microscopic matter

• Atoms eV to keV• Materials 0.1 eV• Nuclei MeV• Elementary particles 100 MeV

to GeV• Largest existing accelerator

(LHC) 16 TeV = 1.6 x 103 GeV• Unification scale 1016 GeV• Planck Energy 1.2 x 1019 GeV

Thermal scales: • Room temperature 1/40 eV• Temperature of the sun surface

6000 degrees ~ 0.5 eV• Temperature to melt nuclei

170 MeV = 2000 x Billions of the temperature at the surface of the sun


The Scale of the Fundamental Forces

http://csep10.phys.utk.edu/astr162/lect/cosmology/forces.htmlhttp://hyperphysics.phy-astr.gsu.edu/hbase/forces/funfor.html

• We know four fundamental forces. (There may exist a fifth)

Interaction Relative Magnitude

Range Action

Strong force 10E(40) Very short Binds nuclei

Electromagnetic force

10E(38) Very long Binds atoms and condensed matter

Weak nuclear force 10E(15) Very short Produces beta decay

Gravity 1 Very long Binds stellar systems

http://csep10.phys.utk.edu/astr162/lect/cosmology/forces.html

http://hyperphysics.phy-astr.gsu.edu/hbase/forces/funfor.html


Some questions about fundamental forces

• Why is there such a mismatch in the range of the various forces?

• Why is there such a huge difference in the strengths of the different forces?

• Why are there 4 different forces, instead of just one?

• At sufficiently high energies they all come together

• But where is gravity?


What is Mass and where does it come from

• Mass defined by Newtons second law:Force = Mass x Acceleration

M = F / a in kg units• But a macroscopic body of mass M

consists of many small pieces that can move around inside the body.

• Where do the little pieces get their mass from?

• LHC and RHIC will provide the answer for that.

• But what about the mass of the Universe; Where does it come from?


First Homework Set, due Sept. 8, 2005

1. Describe briefly the 3 important discoveries that Einstein published in 1905.

2. Who demonstrated that electromagnetic waves exist. What lead to the discovery that light was an electromagnetic wave?

3. Where was Max Planck’s office when he discovered his quantum theory? ((hint: go to the web!)

4. Give the approximate dimensions of the Earth, an ant, an atom and a nucleus, with their appropriate dimensional prefixes.

5. A light-year is a distance. How long is it? (hint: a year = 86,000 s)6. Name the four forces that we encounter in Nature and describe

briefly what action they perform.


How to submit Homework

You must bring the homework to class before the due date It will be returned in class in the next lecture.I will personally grade the homeworkDo not submit homework electronicallyBe brief and to the point in your answers

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