Recent content by slimjim

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    Trouble looking up values of critical temperature for mercury

    I find values for the critical temperature of mercury, but two values are given; one for Hg (α) and one for Hg (β). Does anyone know what the alpha and beta denotes? Here is the page I am referring to (under section titled "Properties of superconducting elements")...
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    Determining exact solutions to a perturbed simple harmonic oscillator

    I did as you suggested. The potential gets shifted left in x, and decreased by a constant amount. Coincidentally, the potential is uniformly decreased by the same value I calculated for E2, the second order perturbation in energy. So I am thinking that the exact ground state energy would...
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    Determining exact solutions to a perturbed simple harmonic oscillator

    Homework Statement Consider as an unperturbed system H0 a simple harmonic oscillator with mass m, spring constant k and natural frequency w = sqrt(k/m), and a perturbation H1 = k′x = k′sqrt(hbar/2m)(a+ + a−) Determine the exact ground state energy and wave function of the perturbed system...
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    Why Is the Conduction Band in Na Metal Half-Filled and Non-Magnetic?

    Homework Statement Describe the ”conduction band” in Na metal. Why it is half-filled and non-magnetic? The Attempt at a Solution Na has electron configuration: [Ne]3s^1 the 3s band is highest in energy and is the conduction band for Na. since Na has 1 electron in the 3s band, and...
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    What are the best options for gaining research experience after undergraduate?

    So I am graduating this spring or summer, 2013, plan to take the GRE next fall and apply to physics phd programs with the aim of going to gradschool in fall of 2014. I hope to spend the time between graduation and gradschool doing some physics related research. This is mostly for the resume...
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    Doubling Computing Power Every Year: Where Will We Be in 50 Years?

    says that computing power at an economic price roughly doubles every year. this relies on the fact that we can stuff more transistors into smaller spaces. we won't reach quantum limitations until atleast 50 years. where will we (humans) be by than?
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    Rest frame angular distribution of meson decay into two photons

    oh i see. picturing a sperical surface surrounding the pion (in its own frame), the probability of a photon emerging through some infinitesimally small surface element would be constant. for a sphere, dA=sin(theta)d∅dθ; ΔP=sin(theta)ΔθΔ∅ phi and theta are orthogonal, so ignoring phi...
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    Rest frame angular distribution of meson decay into two photons

    Say theta is taken from the direction of the pions momentum in the lab frame (call it +z). Then the pion decays into two photons, that when boosted to the lab frame, give the same total momentum as the pion initially. So if the photons emerge along the z axis, could boosting to the lab frame...
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    Rest frame angular distribution of meson decay into two photons

    I paraphrased it from a homework problem. The actual homework question asks to explain why f(θ)=sinθ is the rest frame angular distribution. Which is even less reassuring... but the question doesn't specify the direction in which the pion is traveling in the lab frame, and θ is the usual...
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    Rest frame angular distribution of meson decay into two photons

    Homework Statement consider a pion decaying into 2 photons. In the rest frame of the pion, the two photons must emerge back-to-back photons are equally likely to emerge in any direction. determine the rest frame angular distribution of the emerging photons. Homework Equations ΔP=f(θ)Δθ is...
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    Obtaining the angular momentum state of two spin 1/2 particles for (S=0)

    Homework Statement consider the possible angular momentum states |s,m>, of a system of two spin-1/2 particles construct all possible states with total spin zero (S=0) Homework Equations The Attempt at a Solution if total S of system is zero, m must also equal zero. So the...
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