Ask the Experts   Physics Job Board   University Departments   Einstein eGreetings   Science eStore Local in California? Visit one of our retail stores. XUMP - Science Toys      Ask the Experts: Quantum Mechanics What are quantum numbers? And how many are there? How come the protons in the nucleus of an atom do not spin around like the electrons do? Since antimatter is created when two matter particles are slammed together at high velocities, could the vice versa work and create matter? Is there any experimental proof that an electromagnetic wave has momentum? If Big Bang theory suggests that the universe started out as a homogeneous mass that spread uniformly in all directions, how did we get 'lumps' [stars, galaxies, etc] in the universe? In General Relitivity, Acceleration and Gravity is the same; So does that mean that when matter accelerates it emits gravitons as do a gravitational force does? What is the significance of uncertainty principle in the real world? Why don't the proton and the electron in a hydrogen atom collapse? Would it be easier to remove an electron from second level or the third level? Why? What is a quantum dot? If the Sun is supposed to be producing white light, why does the sun appear yellow to the eye instead of white? If the sun gives off UV rays, does a flame give off a small amount of UV rays as well? Or does the sun give off UV rays because it burns a certain element or chemical compound? If nothing can come out of the black hole, how come the x-rays can be emitted? Why is uranium fissionable and not, say, aluminum? I have read that gravity waves travel at the speed of light; does this mean that gravity waves are a part of the electromagnetic spectrum? Is it possible to have a hollow sphere with a continuous north pole on the outside and a continuous south pole on the inside? What is the Zeeman effect? Some physicists see great potential in superstring theory, while others reject it. What is the alternative to superstring theory? How did Max Planck determine the planck length? From what I understand, Planck time is the amount of time it takes a photon to move Planck length, but what is Planck length and what is it based on? In the EPR paradox by Einstein, is there any information transfer in the process? Is the information different from what we have in a message? How did the Atom obtain it's name? What is the quantum theory of gravity? Is it possible for electrons to quantum tunnel through charged aluminum foil? Is there any practical proof of time dialation on atomic particles? If we have not yet discovered a method of seperating quarks from each other in protons and neutrons, how did scientists discover that protons and neutrons were composed of quarks? Have gluons actually been detected, and if they have, how? How does a laser cool something, as in producing a Bose-Einstein condensate? Is the law of conservation of energy violated for a short or long period of time and can it be experimentally observed? Would I receive more energy from a solar cell if I were to filter everything but UltraViolet light? Or do you get more energy from all wavelengths added together? What is the smallest amount of time? What is the basic difference between the Pauli Exclusion Principle and the Heisenberg Uncertainty Principle? Which is larger, the proton or the neutron? What causes different colors in flames? How are the protons and neutrons held together in a nucleus? What is FET? Which is larger - a quark or an electron? What is nanotechnology and why is it such a buzz in the computer industry? What is the difference between atomic physics and nuclear physics? My son is taking complex numbers in high school, and he is asking 'What are these good for?' I know they are used in electromagnetic calculations, but how? How did thermal blackbody radiation spectrum not fit classical physics and what was done about it? What is a quantum well? What are Eigen Values? Why the masses of proton and neutron are not exactly equal? According to QM, a radioactive atom will decay randomly. But, how many atoms does it take to enforce a predictable half life? And why? What are the fundamental particles that make up a nucleus? What are the odds of me experiencing Quantum Tunneling? If nothing can travel faster then the speed of light, how does one explain Cerenkov Radiation? What's the Pauli-exclusion Principle? When annihilation occurs what happens with the charge of the interacting particles? Is there any gravitational force between two photons? How many oscillations does a caesium atomic clock make in a day? Do sub-atomic particles obey Newtons Laws of motion? How fast (ie: clockspeed in Hz) can a single processor in a computer be? The highest I've read is 4 GHz. What's the limit? Why are there usually more neutrons than protons in a heavy element? Has Pauli's exclusions principle got anything to do with it? I know for a fact that a moving charge can produce a magnetic field. But I'm curious if a moving magnetic field produce a charge? What is CP violation and how does it explain the fact that matter outnumbers antimatter in the universe? What is the physical meaning of a commutator in quantum mechanics? Did they really split the electron? I have heard there is only one component of the atom momentum quantized, (Lx, Ly, Lz) then, does it have an orientation in space? Do molecules have colours? What about electrons, protons and neutrons? I have noticed that many Einstein quotes mention his belief in 'truth and beauty' - I was wondering, is it purely coincidental that two of the six quarks are also named truth and beauty? What is the difference between nuclear fusion and cold fusion? What is the Schrodinger equation, and how is it used? What is the difference between atomic and nuclear physics? What is temperature? Is temperature a measure of the vibrations of matter? If so isn't it related to kinetic energy and therefore not a base quantity? What is the amount of energy given off when an electron and a positron anhilalate? How is time a function of the fabric of nature, and not perception only? How was the mass of a proton determined? If neutrinos have mass, as my physicist nephew from Fermilab says is now the consensus, how can one explain the virtual simultaneous arrival of neutrinos and photons from the Supernove1987A in a Magellanic cloud about 300,000 light years away? I have heard that humans have a wavelength. Is this true? What is a Higgs Particle? What is the densest thing on Earth? How does an atomic clock work? I heard that an electron moving in a certain orbital is actually perpetual mobile - is this true? What is a Bose-Einstein condensate? Photons are Bosons, so why don't they make Bose-Einstein-Condensation? Is it possible to make a perfect vacuum? What is Planck length? What is Planck time? If an electron were increased to the size of an apple, how big, proportionately, would a human being be? What is a neutrino? How are solar sails possible? If photons have no mass, how can they push on something? What force in the universe is the strongest or the most powerful? What does the term 'strangeness' refer to? We talk of positively and negatively charged particles. But what actually is a charge, what is the property of charge caused by? Since oppositely charged particles attract, and gravity is a phenomenon common to all particles, how come the electron is not 'sucked' into the nucleus? What are Feynman diagrams? Could you give good bibliography about QED? Is time quantized? How can something have a negative mass, and what does that mean? What is singularity and why do all laws of physics break down at singularity? I heard that 'bosons' are particles made from a quark and an anti-quark. Is this true? If it is, then how come they do not to annihilate each other? If there is anti-matter, couldn't there be anti-energy? Why is it easier to accelerate an electron to a speed that is close to the speed of light, compared to accelerating a proton to the same speed? Is there any experimental data supporting the existence of gravitons? If there is, how fast do these wave/particles travel? Are they similar to photons? On the atomic level, there is some free space between the electrons and nucleus of atoms (and between the protons and neutrons in the nucleus itself). What 'material' fills these spaces? Dark matter? By what method is the size (or volume) of the universe at the moment of the big bang (or shortly thereafter) determined? Related to this, how is the size of a black hole determined? What is meant when one says that the temperature of the cosmic background radiation is 3K? I heard from a friend recently that a new 'type' of matter has been detected at CERN: neutralinos. Is that true? Could you explain van der Waals' forces to me, and their role in why energy is needed to vaporize water? Assuming the probability of obtaining heads in coin flip is exactly fifty percent, why should a test group of a ten flips produce less accurate results than one of one million flips? How does one electron go through two slits at the same time? In Young's Double-Slit experiment Hawking, Feynman and Brian Greenes ay that one electron goes through both slits at the same time. Why isn't the electron considered a black hole? It does have mass and its radius is infinitely small, isn't it? What is the difference between cathode rays and beta rays since both are basically electrons? What is the significance of the number 137 in physics? My science data book says that the mass of a photon is zero. But how can photon exert radiation pressure, as it occurs in the sun? What is the name for a phenomenon where the presence of the observer changes the nature of the observed? If gamma rays can travel through walls, and radio waves can travel through walls, and they are on opposite ends of the electromagnetic spectrum, then why can't light travel through walls which is right in the middle of the spectrum? Why is there no colour spectrum at the sub-atomic level? Or is there? In a matter-antimatter reaction, is all the material converted into energy? If not, what is the efficiency of the reaction? Are there any laws stating that time must flow in a constant stream (i.e. moments in unbroken succession)? What is the string theory? Who came up with it / discovered it? What is a quark? Please can you (briefly) tell me how the concept of 'non locality', or what Einstein referred to as 'spooky action at a distance' was arrived at? Since there are such things as anti-electrons and anti-protons, is there such a thing as an anti-neutron? Regarding natural units, how can h=c=1, and why is this simplification used? Is it possible to find the radius of an electron? Are the electrons spinning around the nucleus of an atom travelling faster than the speed of sound? Is it possible that a big enough particle accelerator ,(the RHIC for example), could generate a black hole. If so - how? When an electron tunnels from one place to another, does in happen instantaneously, or does it require a finite amount of time? Can things other than electrons tunnel? How is the photon energy related to photon frequency? Which makes more sense: that photons [and other quantum objects] are neither waves nor particles or that they both waves and particles? How fast do electrons travel when moving as an electrical current through copper wire? Everybody knows e=mc2 But what are the units? How many atoms thick is aluminum foil? Who discovered the proton? And how was it discoverd? What exactly is an ELECTRON VOLT as opposed to a VOLT? Is it possible to create an object that is composed of antimatter only? What is the fine-structure constant? What is the Photoelectric Effect? How big is an atom of gold? Where do electrons get the energy to travel at such high speeds? When you said E=mc2 ,what does the c stand for?

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