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Quantum Mechanics in the Macroscopic World

  1. Dec 16, 2004 #1
    I understand most implications of Quantum mechanics on the microscopic world, at least in a non-mathematical sense. However, why is the macroscopic world any different? I understand that there is a change in mass, which affects the Heisenburg Uncertainty Principal to make the uncertainties in momentum and position extremely small, but since we are all just a collection of much smaller particles, why are all our particles behaving according to quantum mechanics and jumping all over each other through our bodies and making a complete mess of any structure. Is the chemical bonding energy between the different atoms in our body really strong enough to overcome the principals of quantum mechanics and hold us together? Or is the large mass of a nucleus (compared to an electron or photon) enough to keep the atom itself from flying all over the place.

    ~Lyuokdea
     
  2. jcsd
  3. Dec 16, 2004 #2

    chroot

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    There's not much of a difference between a "very large number of states" and an "infinite number of states." As the number of discrete states in a quantum-mechanical system becomes very large, the system becomes indistinguishable from a classical system.

    Luckily for us, quantum mechanics doesn't imply that particles "jump all over each other" or anything of the sort.

    - Warren
     
  4. Dec 16, 2004 #3
    I'm not sure I'm exactly getting your explanation. By jumping all over eachother, I was implying the borrowing of energy that can occur on the microscopic world and thus allow quantum tunneling and the like. It would seem then, if there is a probability that this can happen then, everytime you run into a wall, while there is almost zero probability of you going through intact, that there is a possibility that some electrons, or other elementary particles could leave your body and tunnel through the wall, what holds large objects together so that they would have to tunnel completely or not tunnel at all? Or am I simply overstretching the analogy used to get from quantum tunneling to the macroscopic world

    ~Lyuokdea
     
  5. Dec 16, 2004 #4

    chroot

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    The probability of your body tunneling through a wall is so small as to be entirely negligible. The probability's not zero, but it's small enough to be disregarded.

    - Warren
     
  6. Dec 16, 2004 #5
    Right, but, why would your body have to either tunnel or not tunnel, why can't you run into the wall and a couple atoms or molecules tunnel, but not the rest of you. Or for instance, your finger tunnels and your left ear tunnels, but the rest of you doesn't. What is to hold you together as one object instead of a ton of small quarks and electrons. Is the chemical bonding really that strong?

    ~Lyuokdea
     
  7. Dec 17, 2004 #6
    Yes, the chemical bonding is that strong, and when one happens to break, another one (usually with the help of enzymes) is instantly formed, so that an atom, or molecule from the center of our body has to break through millions of bondings consecutively to completely escape. When it reaches our surface, it escape in the form of (dead) skin cells, hair and sweat that we shower off.

    And we do in fact tunnel through ourselves and thin walls, since biological tissue has slight, measurable radioactivity (our carbon-14 are the perhaps the least stable of our atoms). After 250 million years though, even our carbon-14 will not be done tunneling out, so that trillions of years (more than the age of the Universe) would be necessary to fully go trough a wall (enclosure).
     
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