Recent content by andrewm

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    Graduate Are Eigenvalues of a Non-Hermitian Matrix Real?

    OK, I'm not surprised. Thanks anyways.
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    Graduate Are Eigenvalues of a Non-Hermitian Matrix Real?

    Given a 4x4 non-Hermitian matrix, is there any method I can use to prove the eigenvalues are real, aside from actually computing them? I'm looking for something like the converse of the statement "M is Hermitian implies M has real eigenvalues". When can one say that the eigenvalues of a...
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    Calculating Sideways Force on Lens from Laser Power

    Homework Statement A laser of power P with wavelength \lambda is directed through a lens (focal length f) off the optical axis by a distance d. What is the sideways force on the lens? Homework Equations Not sure. The average radiation pressure is I/c, where I is the intensity. But this...
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    Please give me the formula (Newon's law)

    M=0.000000007kg This mass is very small considering the spheres are 2m apart. I always try to notice these things for myself. This helps me be surprised when I get a surprising answer! And often, a surprising answer to a sundry question is a wrong answer.
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    Undergrad Can Events with Zero Probability Actually Occur?

    Physics has never perfectly described the physical world. It is a science of approximations. (It is only approximations!). In physics, there are many P=0 events. And in the real world? I don't know, but that sort of question isn't physics at all! It's philosophy.
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    Schools Theoretical Physics and Graduate School

    I won't be able to give you very good advice, but I do know one thing: most graduate schools require undergraduates with a background in, at least, classical mechanics, electromagnetism, thermal and statistical physics, and some quantum mechanics. From the sounds of it, you will not be able to...
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    Please give me the formula (Newon's law)

    You are not yet ready, mathematically, for physics. And I don't mean formulas; I mean your logic and intuition.
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    Physics I am thinking of getting a Msc in geophysics.

    The geophysicists I've spoken to claim that the field is very lucrative. A PhD in geophysics will often work in the energy sector searching for oil.
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    Approaching School in Engineering: Tips from Richard Feynman & Einstein

    Keep in mind that physics and engineering, like all pursuits in life, require a huge amount of unexciting work. I do not mean to say that physics is boring, but for many courses you are investing in your understanding. It will pay off later. Consider, for instance, how many hours you needed...
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    Engineering Engineering in Undergrad and Physics in Grad school

    Many schools offer programs in Engineering Physics or Engineering Science.
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    Undergrad Throw whatever you have against these 2 equations

    Of course, thanks. I'll try to find a new constraint.
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    Undergrad Throw whatever you have against these 2 equations

    A and B are known parameters. Indeed, I have already tabulated them numerically.
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    Undergrad Throw whatever you have against these 2 equations

    This isn't my homework: I'm doing some physics research and I'm stuck at a simple 2 equations. I want to solve these equations A \cos(\gamma) \sinh(\theta) = \lambda - B \cosh(\theta) A \cos(\gamma) \cosh(\theta) = A \sin(\gamma) - B \sinh(\theta) I'd like to know if there's any way I...
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    Graduate What Happens to the Uncertainty Principle at Absolute Zero?

    Thanks, that's an easy way to remember where zero point energy comes from! I guess I need to start taking my grade-school physics with a grain of salt, don't I? :smile:
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    Graduate What Happens to the Uncertainty Principle at Absolute Zero?

    If \Delta x \Delta p > \frac{\hbar}{2}, what happens at T=0? Since "all motion stops" must we have \Delta x diverge? Or is the zero-point motion allowed to occur at T=0, and only classical kinetic energy is zero?