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A new instability in clustering dark energy? [article]

Farbod Hassani, Julian Adamek, Martin Kunz, Pan Shi, Peter Wittwer
2022 arXiv   pre-print
of motion that are quadratic in the field variables, gives rise to a new instability in the regime of low speed of sound (high Mach number).  ...  In this paper, we study the effective field theory (EFT) of dark energy for the k-essence model beyond linear order.  ...  A Convergence tests In this appendix we discuss the tests performed to validate the results presented in Sec. 3 for the realistic cosmological simulations.  ... 
arXiv:2204.13098v1 fatcat:jospkd42ynhkhgrsbcjv3vclne

Phantom Energy: Dark Energy withw<−1Causes a Cosmic Doomsday

Robert R. Caldwell, Marc Kamionkowski, Nevin N. Weinberg
2003 Physical Review Letters  
Here, we explore the consequences that follow if the dark energy is phantom energy, in which the sum of the pressure and energy density is negative.  ...  Recent evidence for a flat Universe, possibly with a cosmological constant or some other sort of negative-pressure dark energy, has suggested that our fate is the latter.  ...  In such a Universe, certain cosmic questions have new significance. The ''why now?''  ... 
doi:10.1103/physrevlett.91.071301 pmid:12935004 fatcat:w6ywoscwt5hoxa5zkaxlmk5dqy

Planets and Dark Energy [article]

Carl H. Gibson
2008 arXiv   pre-print
The plasma protogalaxies fragment on transition into white-hot planet-mass gas clouds (PFPs) in million-solar-mass clumps (PGCs) that become globular-star-clusters (GCs) from tidal forces or dark matter  ...  The weakly collisional non-baryonic dark matter diffuses to > Mpc scales and fragments to form galaxy cluster halos.  ...  New physical laws are not required by HGD but CDM must be discarded. The choice is between planets and dark energy.  ... 
arXiv:0803.4293v1 fatcat:wxnxjjm24vgh3gfolpecjhzan4

Monodromic Dark Energy [article]

Fabian Schmidt
2017 arXiv   pre-print
Moreover, simple models with non-standard kinetic term result in interesting large-scale structure phenomenology beyond that of standard slow-roll dark energy.  ...  All these scenarios are best constrained in a dedicated search, as current analyses average over relatively wide redshift ranges.  ...  I further thank Alex Vikman for dicussions on gradient instabilities. Finally, I thank the Wissenschaftskolleg zu Berlin, where this paper was completed, for hospitality.  ... 
arXiv:1709.01544v3 fatcat:sow4kdtjpnbkpia4ovzvcghv3u

Foreword: Dark energy and CMB

Scott Dodelson, Dragan Huterer
2015 Astroparticle physics  
These seeds began to grow via gravitational instability during the epoch in which dark matter dominated the energy density of the universe, transforming small perturbations laid down during inflation into  ...  Over the past few billion years, we have entered a new phase, during which the expansion of the Universe is accelerating presumably driven by yet another substance, dark energy.  ... 
doi:10.1016/j.astropartphys.2014.08.002 fatcat:5ocn2mxjyjcpbhgsmuxo2c7eki

Dark Energy and CMB [article]

S. Dodelson, K. Honscheid, K. Abazajian, J. Carlstrom, D. Huterer, B. Jain, A. Kim, D. Kirkby, A. Lee, N. Padmanabhan, J. Rhodes, D. Weinberg
2013 arXiv   pre-print
The sub-group "Dark Energy and CMB" prepared a series of papers explaining and highlighting the physics that will be studied with large galaxy surveys and cosmic microwave background experiments.  ...  The American Physical Society's Division of Particles and Fields initiated a long-term planning exercise over 2012-13, with the goal of developing the community's long term aspirations.  ...  Finally, a suite of novel probes of gravity and dark energy can discover signatures of modified gravity and new physics in the dark sector.  ... 
arXiv:1309.5386v2 fatcat:dpsnu5p6drbilj3ppqzdutayt4

Dark Energy

Miao Li, Xiao-Dong Li, Shuang Wang, Yi Wang
2011 Communications in Theoretical Physics  
We review the problem of dark energy, including a survey of theoretical models and some aspects of numerical studies.  ...  Finally, one should note that holographic dark energy solves both the old and new cosmological problem in a consistent way.  ...  Thus here we mainly review the so called new agegraphic dark energy model [175] .  ... 
doi:10.1088/0253-6102/56/3/24 fatcat:thxqg3zkezcslna4gi75fzhloy

New Constraints on Dark Energy [article]

Alessandro Melchiorri
2004 arXiv   pre-print
New Cosmic Microwave Background, Galaxy Clustering and Supernovae type Ia data are increasingly constraining the dark energy component of our Universe.  ...  While the cosmological constant scenario remains consistent with these new tight constraints, the data does not rule out the possibility that the equation of state parameter is less than -1.  ...  Λ or a dark energy component (see e.g. 5 ). 2 Alternatives to Λ A complete treatment of the possible contenders to the dark energy throne can be found in several and excellent recent reviews (see e.g.  ... 
arXiv:astro-ph/0406652v2 fatcat:7zuv6m3f6zg5rdmibt4sk7iree

Cosmological Parameters, Dark Energy and Large Scale Structure [article]

S.E. Deustua, R. Caldwell, P. Garnavich, L. Hui, A. Refregier
2002 arXiv   pre-print
We review the current status of cosmological parameters, dark energy and large-scale structure, from a theoretical and observational perspective.  ...  We then describe the recent evidence for dark energy from Type Ia supernovae.  ...  Furthermore, these new values have provided a concordance model, a flat universe with a significant component of "dark energy" which accelerates the expansion in the current epoch, which challenges our  ... 
arXiv:astro-ph/0207293v1 fatcat:s24gkl2io5fjrm6wlokbk7w4ea

Galaxy clustering and dark energy

Dipak Munshi, Cristiano Porciani, Yun Wang
2004 Monthly notices of the Royal Astronomical Society  
We find that there is a degeneracy between the dark energy equation of state and the way galaxies populate dark matter haloes; objects are more biased in models with more negative values of dark energy  ...  In particular, we show that the abundance and spatial distribution of galaxy clusters at intermediate redshifts strongly depend on the dark energy equation of state.  ...  It is a pleasure for DM to acknowledge many fruitful discussions with members of Cambridge Leverhulme Quantitative Cosmology Group.  ... 
doi:10.1111/j.1365-2966.2004.07498.x fatcat:6svzwemhmbd6bnui32rva5asj4

Problems of vacuum energy and dark energy [article]

A.D. Dolgov
2004 arXiv   pre-print
A simple description of the vacuum energy (cosmological constant) problem for non-experts is presented. Basic features of cosmology with non-zero vacuum energy are discussed.  ...  The idea of dynamical adjustment is considered in some more detail.  ...  This new contribution to cosmological energy density got the name dark energy.  ... 
arXiv:hep-ph/0405089v1 fatcat:ioj2wlqpm5h75dmqmfwvr7reki

INSTABILITY OF QCD GHOST DARK ENERGY MODEL

ESMAEIL EBRAHIMI, AHMAD SHEYKHI
2011 International Journal of Modern Physics D  
We investigate the instability of the ghost dark energy model against perturbations in different cases.  ...  At first we discuss the noninteracting ghost dark energy model in a flat FRW universe and find out that such a model is unstable due to the negativity of the v_s^2 in all epoches.  ...  We investigate the instability of the ghost dark energy model against perturbations in different cases.  ... 
doi:10.1142/s021827181102041x fatcat:65dfqw2mw5at5bpgkfolplrs2y

Galaxy clusters and structure formation in quintessence versus phantom dark energy universe

Zacharias Roupas, Minos Axenides, George Georgiou, Emmanuel N. Saridakis
2014 Physical Review D  
The self-gravitating gas in the Newtonian limit is studied in the presence of dark energy with a linear and constant equation of state.  ...  in case of quintessence or phantom dark energy, respectively, that satisfy a linear equation of state.  ...  In section III we study the galaxy clusters, investigating the effect of dark energy on the clusters' density profile and proposing a method to constrain the dark energy equation of state, based on clusters  ... 
doi:10.1103/physrevd.89.083002 fatcat:j7agmn22szbsnds6jnxu4hoyhm

The Quintom Model of Dark Energy [article]

Bo Feng
2006 arXiv   pre-print
In this paper I give a brief review on the recently proposed new scenario of dark energy model dubbed Quintom.  ...  Quintom describes the dynamical dark energy models where the equation of state getting across the cosmological constant boundary during evolutions.  ...  Basing on these facts we proposed a new model of dark energy dubbed Quintom [11] , in the sense that the required behavior of the dynamical dark energy combines that of quintessence and phantom.  ... 
arXiv:astro-ph/0602156v1 fatcat:vhdlmbo5gzgrtpc4og765b5zai

Dark Energy simulations

Marco Baldi
2012 Physics of the Dark Universe  
in the development and application of specific algorithms designed to probe a wide range of Dark Energy scenarios.  ...  of Dark Energy.  ...  This work has been supported by the DFG Cluster of Excellence ''Origin and Structure of the Universe'' and by the TRR33 Transregio Collaborative Research Network on the ''DarkUniverse''.  ... 
doi:10.1016/j.dark.2012.10.004 fatcat:6kd5py6fkjewxjmwcmj77qichq
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