REVIEW
QCD Plasma Instabilities and Bottom-Up Thermalization
High Energy Physics - Phenomenology · Submitted 25 Jul 2003 · 40 references
Pith's verdict: The paper that killed the first stage of bottom-up thermalization; the central argument holds, but Section IV is void and the authors' own erratum says so.
T0 · AI review
Why Pith says this
Highlight any text to comment on it.
Referee report
The paper
The paper claims
Anisotropic momentum distributions in an early quark-gluon plasma drive Weibel and two-stream instabilities that grow faster than the plasma expands, invalidating the first stage of bottom-up thermalization.
The reading
Extended reading notes
Core claim
The first stage of the bottom-up thermalization scenario is drastically modified by QCD plasma instabilities, which grow on a timescale t_growth ~ 1/|m_soft| ~ sqrt(tau/Qs) that is parametrically shorter than the expansion time tau for Qs tau >> 1. The paper states that 'the first stage of the original bottom-up thermalization scenario cannot, even briefly, be qualitatively accurate.' If correct, the standard picture of how a quark-gluon plasma equilibrates after a heavy-ion collision is wrong at its earliest stage.
Load-bearing premise
The collisionless approximation for the hard particles, justified in Section I A by the estimate t_col ~ (Qs tau)^{2/3}/Qs >> t_growth ~ sqrt(tau/Qs) for Qs tau >> 1 (eqs 1.8-1.9). If collisions damp the unstable modes faster than they grow, the central claim that instabilities dominate the first stage fails. The estimate is parametric and depends on the assumed scaling of the soft scale m_soft and the hard-particle density.
Original abstract
We study the role of QCD plasma instabilities in non-equilibrium quark-gluon plasmas. First, we argue that such instabilities must drastically modify the "bottom-up" thermalization scenario for heavy-ion collisions. Second, we discuss conditions for the existence of instabilities in a more general context than previously treated in the QCD literature. We also give a thorough qualitative review of the origin of instabilities. We discuss some mechanisms whereby the growth of plasma instabilities saturates. Finally, we solve explicitly for instabilities and their growth rates for two extreme cases of anisotropic non-equilibrium plasmas that can be treated relatively simply and analytically: $f(\p) = F(p_\perp) \delta(p_z)$ and $f(\p) = F(p_z) \delta^{(2)}(p_\perp)$, where $f(\p)$ is the distribution of particles in momentum space.
The compiled record
The paper's own sentences, arranged, kept beside the review and separate from it. Each label is drawn from a closed vocabulary; the number beside it is the probability the classifier gave that label. Numbers in the tables are the authors', checked by code. No sentence in this record was written by a model.
The abstract, sentence by sentence
We study the role of QCD plasma instabilities in non-equilibrium quark-gluon plasmas. First, we argue that such instabilities must drastically modify the "bottom-up" thermalization scenario for heavy-ion collisions. Second, we discuss conditions for the existence of instabilities in a more general context than previously treated in the QCD literature. We also give a thorough qualitative review of the origin of instabilities. We discuss some mechanisms whereby the growth of plasma instabilities saturates. Finally, we solve explicitly for instabilities and their growth rates for two extreme cases of anisotropic non-equilibrium plasmas that can be treated relatively simply and analytically: $f(\p) = F(p_\perp) \delta(p_z)$ and $f(\p) = F(p_z) \delta^{(2)}(p_\perp)$, where $f(\p)$ is the distribution of particles in momentum space.
background contribution method result interpretation main claim
| # | sentence | role | the authors' own work | states the main conclusion | strength |
|---|---|---|---|---|---|
| s0 | We study the role of QCD plasma instabilities in non-equilibrium quark-gluon plasmas. | contribution 0.81 | 0.83 | 0.05 | unclear 0.57 |
| s1 | First, we argue that such instabilities must drastically modify the "bottom-up" thermalization scenario for heavy-ion collisions. | contribution 0.40 | 0.72 | 0.62 | asserted 0.68 |
| s2 | Second, we discuss conditions for the existence of instabilities in a more general context than previously treated in the QCD literature. | contribution 0.99 | 0.82 | 0.05 | asserted 0.69 |
| s3 | We also give a thorough qualitative review of the origin of instabilities. | contribution 0.63 | 0.70 | 0.03 | asserted 0.71 |
| s4 | We discuss some mechanisms whereby the growth of plasma instabilities saturates. | contribution 0.97 | 0.76 | 0.05 | asserted 0.56 |
| s5 | Finally, we solve explicitly for instabilities and their growth rates for two extreme cases of anisotropic non-equilibrium plasmas that can be treated relatively simply and analytically: $f(\p) = F(p_\perp) \delta(p_z)$ and $f(\p) = F(p_z) \delta^{(2)}(p_\perp)$, where $f(\p)$ is the distribution of particles in momentum space. | contribution 0.58 | 0.96 | 0.11 | asserted 1.00 |
What was examined, and what was not
- arXiv listing abstract v4
- full text
- figures and tables
- references and citing sentences
- relations to other papers
- P abstract
- S sections
- T body sentences
- C citations
- R cross-paper relations
Figures
Figures reproduced from arXiv:hep-ph/0307325 by the authors.
References
How the literature uses it
50 arXiv papers cite this in 61 sentences
Papers whose main result relates to this one's
States the same result 1 paper
-
We investigate the impact of plasma instabilities on the first stage of the ``bottom-up'' thermalization scenario in which such a two-component plasma emerges, and find that even in the case of non-abelian saturation instabilities qualitatively change the bottom-up picture.
The impact of QCD plasma instabilities on bottom-up thermalization · 0.87
Papers citing it · 41 sentences without a confident label
Uses its method or tool 1 paper
-
The non-equilibrium rates are enhanced using a bremsbremstrahlung ansatz analogous to the complete leading order (LO) thermal rate [ref] .
Non-equilibrium photons from the bottom-up thermalization scenario · Introduction · 0.91
Uses its data or values 1 paper
-
An estimate in [ref] is that the saturation value for mode number $q$ is $gB≃q^2$ (see however, [ref] ).
Spin polarization of heavy quarks in matter: predictions from effective field theories · Heavy Quark Effective Theory in matter · 0.83
Cites it as background 18 papers
-
In the case of a non-equilibrium QGP it is still possible to make studies of the collective modes of the system, however, the situation is complicated by the presence of unstable gluonic modes related to the chromo-Weibel instability [ref] .
Collective modes of a collisional anisotropic quark-gluon plasma · Introduction · 0.82
-
The identification of the deconfined phase of quarks and gluons at the Relativistic Heavy Ion Collider, a phase akin to a nonabelian plasma, has led to a number of investigations on instabilities in a nonabelian plasma [ref] .
A Note on Schwinger Mechanism and a Nonabelian Instability in a Nonabelian Plasma · Introduction · 0.99
-
There are important qualitative differences between QED and QCD plasma instabilities [ref] .
Non-abelian plasma instabilities for strong anisotropy · Introduction · 0.83
Discussion
Disagree with the review, or know something it missed? Leave a comment, highlight any passage above to comment on it, or challenge this review formally.