How is the Power Spectrum of Matter Density Field Defined?

AI Thread Summary
The power spectrum of the matter density field is defined by the equation P_{xx}(k)=(2\pi^3)\delta(k-k^\prime)<x(k)x(k^\prime)>, which incorporates a factor of (2\pi^3). An alternative definition is presented as P_{yy}(k)=\delta(k-k^\prime)<y(k)y(k^\prime)>, which raises the question of whether the (2\pi^3) factor has been absorbed into the correlation function in this context. The discussion highlights the importance of understanding the role of these constants in the definitions of power spectra. Clarifying these definitions is crucial for accurate interpretations in cosmological studies. Overall, the relationship between the two equations is central to the analysis of matter density fields.
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Homework Statement
The definition of power spectrum of matter density field is given by eq (1). I have also seen definitions of power spectra given by eq (2) . Does this mean ##(2\pi^3)## has been absorbed in the correlation function?
Relevant Equations
##P_{xx}(k)=(2\pi^3)\delta(k-k^\prime)\langle x(k)x(k^\prime)\rangle##

##P_{yy}(k)=\delta(k-k^\prime)\langle y(k)y(k^\prime)\rangle##

<Mentor: edit latex>
The definition of power spectrum of matter density field is given by eq(1). I have also seen definitions of power spectra given by eq(2) . Does this mean (2\pi^3) has been absorbed in the correlation function?

$$P_{xx}(k)=(2\pi^3)\delta(k-k^\prime)<x(k)x(k^\prime)>$$ .. (1)
$$P_{yy}(k)=\delta(k-k^\prime)<y(k)y(k^\prime)> $$.. (2)
 
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