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    #1

    across a cosmological bounce

    Does "across a cosmological bounce" mean "during the entire process of a cosmological bounce"?


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    We study quantum cosmology with conformal matter comprising a perfect radiation fluid and a number of conformally coupled scalar fields. Focusing initially on the collective coordinates (minisuperspace) associated with homogeneous, isotropic backgrounds, we are able to perform the quantum gravity path integral exactly. The evolution describes a “perfect bounce”, in which the Universe passes smoothly through the singularity. We extend the analysis to spatially flat, anisotropic universes, treated exactly, and to generic inhomogeneous, anisotropic perturbations treated at linear and nonlinear order. This picture provides a natural, unitary description of quantum mechanical evolution across a cosmological bounce. We provide evidence for a semiclassical description in which all fields pass “around” the cosmological singularity along complex classical paths.

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    PHYSICAL REVIEW LETTERS


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    #2

    Re: across a cosmological bounce

    Given that "The evolution describes a 'perfect bounce',” it appears that the quantum mechanical evolution is the bounce. Yes, that is the usage of 'across' here - covering the whole of something, not the usual meaning of going from one side to the other.

    Examples:
    "It applies across the whole spectrum."
    "He seems to be across the entire project."



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    #3

    Re: across a cosmological bounce

    By the way, does the first sentence "We study quantum cosmology with conformal matter comprising a perfect radiation fluid and a number of conformally coupled scalar fields" mean:

    "By using the concept of conformal matter, which comprises a perfect radiation fluid and
    a number of conformally coupled scalar fields, we study quantum cosmology"?

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    #4

    Re: across a cosmological bounce

    Would anyone who's familiar with physics language like to give a hand?

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    #5

    Re: across a cosmological bounce

    The comma doesn't belong. I don't know if conformal matter requires a defining clause or a non-defining one (since I don't know what it is), but the comma doesn't exist in the original.

    I don't think "the concept of" belongs. Consider: "We study bacteria with a microscope" OK. "By using the concept of a microscope, we study bacteria." No, we need to use an actual microscope.
    I don't know what the sentence means, or what conformal matter is, so I can't really say whether your sentences mean the same thing.

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    #6

    Re: across a cosmological bounce

    Rather than studying something with the concept of something else, which isn't really possible, you can apply the concept of x to the study of y.
    I am not a teacher.

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    #7

    Re: across a cosmological bounce

    Does "this picture" refer to "the picture that is described by the extended analysis"?

    We extend the analysis to spatially flat, anisotropic universes, treated exactly, and to generic inhomogeneous, anisotropic perturbations treated at linear and nonlinear order. This picture provides a natural, unitary description of quantum mechanical evolutionacross a cosmological bounce. We provide evidence for a semiclassical description in which all fields pass “around” the cosmological singularity along complex classical paths.

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    #8

    Re: across a cosmological bounce

    Yes.

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