Quintic NLS: Difference between revisions

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====Quintic NLS on <math>R</math>====
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* This equation may be viewed as a simpler version of [#dnls-3_on_R cubic DNLS], and is always at least as well-behaved. It has been proposed as a modifiation of the Gross-Pitaevski approximation for low-dimesional Bose liquids [[Bibliography#KolNewStrQi2000|KolNewStrQi2000]]
The quintic [[NLS]] has been studied [[Quintic NLS on R|on R]], [[Quintic NLS on R|on T]],
* Scaling is <math>s_c = 0\,</math>, thus this is an [#L^2-critical_NLS L^2 critical NLS].
[[Quintic NLS on R2|on R^2]], and [[Quintic NLS on R3|on R^3]].
* LWP is known for <math>s \ge 0\,</math> [[Bibliography#CaWe1990|CaWe1990]], [[Bibliography#Ts1987|Ts1987]].
** For <math>s=0\,</math> the time of existence depends on the profile of the data as well as the norm.
** Below <math>L^2\,</math> we have ill-posedness by Gallilean invariance considerations in both the focusing [KnPoVe-p] and defocusing [CtCoTa-p2] cases.
* GWP for <math>s>4/9\,</math> in the defocussing case [Tzi-p]
** For <math>s>1/2\,</math> this is in [[Bibliography#CoKeStTkTa-p6 |CoKeStTkTa-p6]]
** For <math>s>2/3\,</math> this is in [[Bibliography#CoKeStTkTa-p4 |CoKeStTkTa-p4]].
** For <math>s > 32/33\,</math> this is implicit in [[Bibliography#Tk-p |Tk-p]].
** For <math>s\ge 1\,</math> this follows from LWP and Hamiltonian conservation.
** One has GWP and scattering for small <math>L^2\,</math> data for any quintic non-linearity. The corresponding problem for large <math>L^2\,</math> data and defocussing nonlinearity is very interesting, but probably very difficult, perhaps only marginally easier than the corresponding problem for the [#Cubic_NLS_on_R^2 2D cubic NLS]. It would suffice to show that the solution has a bounded <math>L^6\,</math> norm in spacetime.
** Explicit blowup solutions (with large <math>L^2\,</math> norm) are known in the focussing case [[Bibliography#BirKnPoSvVe1996|BirKnPoSvVe1996]]. The blowup rate in <math>H^1\,</math> is <math>t^{-1}\,</math> in these solutions. This is not the optimal blowup rate; in fact an example has been constructed where the blowup rate is <math>|t|^{-1/2} (log log|t|)^{1/2}\,</math>[Per-p]. Furthermore, one always this blowup behavior (or possibly slower, though one must still blow up by at least <math>|t|^{-1/2}\,</math>) whenever the energy is negative [MeRap-p], [MeRap-p2], and one either assumes that the mass is close to the critical mass or that <math>xu\,</math> is in <math>L^2\,</math>.
*** One can modify the explicit solutions from [[Bibliography#BirKnPoSvVe1996|BirKnPoSvVe1996]] and in fact create solutions which blow up at any collection of specified points in spacetime [[Bibliography#BoWg1997|BoWg1997]], [[Bibliography#Nw1998|Nw1998]].
* ''Remark'': This equation is pseudo-conformally invariant. GWP results in <math>H^s\,</math> automatically transfer to GWP and scattering results in <math>L^2(|x|^s)\,</math> thanks to the pseudo-conformal transformation.
* Solitons are <math>H^1\,</math>-unstable.


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====Quintic NLS on <math>T</math>====
 
* This equation may be viewed as a simpler version of cubic DNLS, and is always at least as well-behaved.
* Scaling is <math>s_c = 0\,</math>.
* LWP is known for <math>s > 0\,</math> [[Bibliography#Bo1993|Bo1993]].
** For <math>s < 0\,</math> the solution map is not uniformly continuous from <math>C^k\,</math> to <math>C^{-k}\,</math> for any <math>k\,</math> [CtCoTa-p3].
* GWP is known in the defocusing case for <math>s > 4/9\,</math> (De Silva, Pavlovic, Staffilani, Tzirakis)
** For <math>s > 2/3\,</math> this is commented upon in [Bo-p2] and is a minor modification of [CoKeStTkTa-p].
** For <math>s \ge 1\,</math> one has GWP in the defocusing case, or in the focusing case with small <math>L^2\,</math> norm, by Hamiltonian conservation.
*** In the defocusing case one has GWP for random data whose Fourier coefficients decay like <math>1/|k|\,</math> (times a Gaussian random variable) [[Bibliography#Bo1995c|Bo1995c]]; this is roughly of the regularity of <math>H^{1/2}\,</math>. Indeed one has an invariant measure. In the focusing case the same result holds assuming the <math>L^2\,</math> norm is sufficiently small.
 
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====Quintic NLS on <math>R^2</math>====
 
* Scaling is <math>s_c = 1/2\,</math>.
* LWP is known for <math>s \ge 1/2\,</math> [[Bibliography#CaWe1990|CaWe1990]].
** For <math>s=1/2\,</math> the time of existence depends on the profile of the data as well as the norm.
** For <math>s<s_c\,</math> we have ill-posedness, indeed the H^s norm can get arbitrarily large arbitrarily quickly [CtCoTa-p2]. In the focusing case we have instantaneous blowup from the virial identity and scaling.
* GWP for <math>s \ge 1\,</math> by Hamiltonian conservation.
** This has been improved to <math>s > 1-e\,</math>- in [[Bibliography#CoKeStTkTa2003b|CoKeStTkTa2003b]]. This result can of course be improved further.
** Scattering in the energy space [[Bibliography#Na1999c|Na1999c]]
** One also has GWP and scattering for small <math>H^{1/2}\,</math> data for any quintic non-linearity.
 
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====Quintic NLS on <math>R^3</math>====
 
* Scaling is <math>s_c = 1\,</math>.
* LWP is known for <math>s \ge 1\,</math> [[Bibliography#CaWe1990|CaWe1990]].
** For <math>s=1\,</math> the time of existence depends on the profile of the data as well as the norm.
** For <math>s<s_c\,</math> we have ill-posedness, indeed the <math>H^s\,</math> norm can get arbitrarily large arbitrarily quickly [CtCoTa-p2]. In the focusing case we have instantaneous blowup from the virial identity and scaling.
* GWP and scattering for <math>s\ge 1\,</math> in the defocusing case [CoKeStTkTa-p]
** For radial data this is in [Bo-p], [[Bibliography#Bo1999|Bo1999]].
** Blowup can occur in the focussing case from Glassey's virial identity.
 
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Latest revision as of 00:05, 18 August 2006


The quintic NLS has been studied on R, on T, on R^2, and on R^3.