What t is eve very ryth thing ng made of? The he quest f t - PowerPoint PPT Presentation

What t is eve very ryth thing ng made of? The he quest f t for the r the ulti ltimate te buildi lding b ng blo locks cks of the physic ical un unive iverse. Soren Sorensen Department of of Physics and As Astron onom omy Uni University o of T Tenne nnessee, Kno noxville

Wh What t is th the Wo World made o of? Probably the most fundamental question one can ask next to “Does God Exist?” Thales of Miletus (~624 - ~547 BC) Start of philosophy and science. Everything is made of water

The L Lego o Block lock A Approa oach ch Reduce the complex forms and materials to one (or a few) fundamental building blocks

The L Layers of S of Scie cience ce In a given field of science we can use a particular set of fundamental building blocks. Usually the number and diversity of the building blocks tends to increase as we learn more and more about the particular layer of science. Eventually we realize that all the building blocks have an internal structure and can be described by a much smaller set of more fundamental entities, which then become the new fundamental building blocks

The Qu Quant ntum L Ladder Living Organisms, Man-made Structures Cells, Crystals, Materials

Biolog iologica ical C l Cells lls  Mole olecule cules Molecules Cells have an internal These cell “building blocks” structure: are in turn made of: Nucleus, Ribosomes, Centriolos, Cytoplasm, Membranes, Axions, etc.

The Qu Quant ntum L Ladder Living Organisms, Man-made Structures Cells, Crystals, Matter Molecules

Mole olecule cules  Ato toms Proteins Complex Benzene Rings NaCl – “Salt” The building blocks for all molecules are: Atoms

The Qu Quant ntum L Ladder Living Organisms, Man-made Structures Cells, Crystals, Materials Molecules Atoms

Ato toms Each element in the Periodic Table corresponds to a particular atom. Mendeleyev discovered how to order the atoms in the Periodic Table, but he did not understand WHY the table had this structure. Currently we know ~118 different elements. Problem: There are too many different building blocks.

Internal S l Struct uctur ure of t of the A Atom om All atoms can be constructed from only three fundamental building blocks: Electrons Early models of the Atom Protons Neutrons The atom consists of negative electrons orbiting a positive nucleus Bohr – The atomic nucleus consists of Rutherford positive protons and neutral Atom neutrons

Comb ombin inin ing p prot oton ons a and neut utron ons in into o atomic omic nucle uclei 288 stable nuclides ~3,000 known nuclides ~7,000 possible nuclides

The Qu Quant ntum L Ladder Living Organisms, Man-made Structures Cells, Crystals, Materials Molecules Atoms Neutrons, Protons, Electrons

“Elementa tary” P Parti ticles In the period 1930 – 1970 hundreds of new “elementary” particles were discovered. Problem: Too many “elementary” particles The Lepton Family (6): Heavy Electrons and nearly undetectable neutrinos The Baryon Family (~120): heavy protons and neutrons The Meson Family (~140): Similar to Baryons, but lighter

“The Period iodic T ic Table le” of of Ele leme mentary P Particle icles The Eightfold Way Murray Gell-Mann and Yuval Nee’man (1961)

The Q Quarks rks The solution: Three simple building blocks called Quarks (1964) Quark Sym- Charge Strange- Anti-Quark Sym- Charge Strange- bol ness bol ness e e Up u 2/3 0 Anti-Up -2/3 0 u Down d -1/3 0 Anti-Down 1/3 0 d Strange s 2/3 -1 Anti-Strange -2/3 1 s Baryons: qqq or Baryons: qqq Mesons: q q-bar q-bar q-bar q-bar

The Qu Quant ntum L Ladder Living Organisms, Man-made Structures Cells, Crystals, Materials Molecules Atoms Neutrons, Protons, Electrons Quarks and Leptons

The Eigh ghtf tfold Wa Way Explained

The S Standard rd M Model

Qua uark S Struct ucture of M of Matter

Mor ore t than j jus ust qua quarks 3 Families

More t than ju n just st quarks s and nd lept ptons: ns: Fo Force P Particles

One One Fo Force ? ?? Distance: 10 -35 m 10 -19 m At very small distances (equivalent to very high temperatures) it seems as if all the known forces might be unified into ONE FORCE.

How c w can we we s study quarks rks? To s o stud udy small objects, like ke q quarks rks, we we n need large ge acce ccele lerator ors.

How c w can we we s study quarks rks? Larg rge Hadro ron Collider i r in Swi witzerl rland/Fra rance

How c w can we we s study quarks rks? Larg rge Hadro ron Collider i r in Swi witzerl rland/Fra rance

How c w can we we s study quarks rks? The A e ALICE D Det etec ector

How c w can we we s study quarks rks? Result ult of collis of collision ion of of two h o heavy a atomic omic nucle uclei

It s t sta tarts ts to to b be “ “messy” “Fundamental” Particles as of today: 6 quarks 6 anti-quarks 6 leptons 6 anti-leptons graviton photon 3 weak-force carriers (W+, W-, Z) 8 gluons = 37 “fundamental” particles Problem: Can we explain all these “fundamental” particles in terms of something even simpler ???

Maybe: S Supe perst string ngs Hypothesis: All fundamental particles are different vibrational modes (excitations) of a fundamental entity: The Superstring

The Qu Quant ntum L Ladder Living Organisms, Man-made Structures Cells, Crystals, Materials Molecules Atoms Elementary Particles Quarks and Leptons Super- strings ?

Vib ibratin ing a and Collid ollidin ing Sup uperstrin ings Two types of strings: Open strings and Closed Strings Different modes of vibration (excitation) will correspond to different types of fundamental particles. However, at the moment we don’t really understand the connection between the vibrations of the string and the fundamental particles

AL ALL In Intera ractions All interactions are just merging of strings What the world might look like or at the smallest possible scales splitting up of a string

Rolled- up d p dimensi nsions ns The Superstring model is extremely complicated mathematically We think we live in a 3-dimensional space (+ 1 time dimension) But the Superstring model requires that we live in a 9-dimensional space, but with 6 dimensions “rolled up” (+ 1 time dimension) A 1-dimensional string (a rope) is really 2-dimensional when viewed at high resolution (small distances)

Supe perst string ngs i s in n many ny d dimensi nsions ns Every point in our normal 3- dimensional space is really a 6-dimensional space 2-dim space with 2 curled-up dimensions (Calabi-Yau Space) (a sphere) in each point 2-dim space with 6 curled-up dimensions (Calabi-Yau Space) in each point

Supe perst string ngs: s: P Pro a and nd Con Pro : Edward Witten Brian Greene Princeton Columbia The concept of the superstring is physically and mathematically appealing The superstring model can explain many theoretical problems in modern physics Con : Lee Smolin Phil Anderson Perimeter Institute Princeton The superstring model is just a The superstring model is just theoretical construction that can not be one of several exciting experimentally verified. It could be “The possibilities for new physics. Ether Theory” of the 21 st century. Quantum Gravity. Very controversial model. The physicists are having heated debates as to whether this model makes sense.

Summary ry Living Organisms, Cells, Crystals, Man-made Structures Materials Quarks and ??? Super- Elementary Leptons strings ? Atoms Molecules Particles Will ll the there be an end?