Cosmology Beyond the Standard Model

Transcription

1 Alex Leithes (QMUL) Cosmology Beyond the Standard Model QMUL Outreach /21 Cosmology Beyond the Standard Model

2 Alex Leithes (QMUL) Cosmology Beyond the Standard Model QMUL Outreach /21 What is Cosmology? We re in the Astronomy Unit so...

3 What is Cosmology?? Alex Leithes (QMUL) Cosmology Beyond the Standard Model QMUL Outreach /21

4 Alex Leithes (QMUL) Cosmology Beyond the Standard Model QMUL Outreach /21 What is Cosmology?

5 Section 1 Section 2 Section 3 What is Cosmology?? Alex Leithes (QMUL) Cosmology Beyond the Standard Model QMUL Outreach /21

6 Section 1 Section 2 Section 3 What is Cosmology? Alex Leithes (QMUL) Cosmology Beyond the Standard Model QMUL Outreach /21

7 Alex Leithes (QMUL) Cosmology Beyond the Standard Model QMUL Outreach /21 What is Cosmology??

8 Alex Leithes (QMUL) Cosmology Beyond the Standard Model QMUL Outreach /21 What is Cosmology? Well... not really...

9 Yes, but one slice in time... Alex Leithes (QMUL) Cosmology Beyond the Standard Model QMUL Outreach /21 What is Cosmology?

10 Evolution though time. Alex Leithes (QMUL) Cosmology Beyond the Standard Model QMUL Outreach /21 What is Cosmology?

11 Alex Leithes (QMUL) Cosmology Beyond the Standard Model QMUL Outreach /21 What is the Standard Model of Cosmology (ΛCDM)?

12 My work to date - beyond ΛCDM First project: Analytical work... Theoretical work performed mathematically - equation manipulation and construction Non standard cosmology - Conserved Quantities and the Evolution of Perturbations in Lemaître-Tolman-Bondi Cosmology (LTB) But what if the universe is not homogeneous on large scales? What if the universe is inhomogeneous on some larger scale? WHAT IF THE APPARENT ACCELERATING EXPANSION OF THE UNIVERSE IS IN FACT DISTANCE DEPENDENT EXPANSION? What if the growth of structure in the universe is governed by perturbations around an inhomogeneous background cosmology? Simplest of these to investigate: Lemaître-Tolman-Bondi Cosmology Alex Leithes (QMUL) Cosmology Beyond the Standard Model QMUL Outreach /21

13 arxiv: but... Alex Leithes (QMUL) Cosmology Beyond the Standard Model QMUL Outreach /21 My work to date - beyond ΛCDM As you can tell from the mass of text above quite technical stuff, plus the arxiv description for the paper, 16 pages, 0 figures... Conclusion and Further Research ζ SMTP = H X + 2H Y 3 ρ δp nad Research already extended to other spacetimes i.e. ζsmtp already extended to Lemaitre and FRW ζ SMTP can provide a useful analytical check for numerical codes in perturbed LTB/inhomogeneous spacetimes... as described in Bartelmann et al. e.g. potentially useful in study of structure formation in large voids (see e.g Das et al.)

14 Alex Leithes (QMUL) Cosmology Beyond the Standard Model QMUL Outreach /21 My work to date - beyond ΛCDM... did get to travel to COSMO 2014 in Chicago to talk about my work :)

15 Alex Leithes (QMUL) Cosmology Beyond the Standard Model QMUL Outreach /21 My work to date - beyond ΛCDM Second project: Numerical work... Small amount of analytical work plus loads of coding... Non standard cosmology - Coupled Quintessence (Not Λ)!

16 Alex Leithes (QMUL) Cosmology Beyond the Standard Model QMUL Outreach /21 Beyond Lambda - Why Coupled Quintessence? Why Coupled Quintessence? Late time accelerated expansion - simplest solution: Cosmological Constant, Λ, Dark Energy? - problems e.g. coincidence Alternatives: one or more scalar fields - non-constant or dynamical Dark Energy Coupled Quintessence: Canonical scalar field(s), φ, with potential V (φ), interacting gravitationally with all components, and through couplings between DE and CDM components - solves problems e.g. coincidence (Quintessence alone), breaking tracking (when Coupled) - Coupled = Interacting

17 Alex Leithes (QMUL) Cosmology Beyond the Standard Model QMUL Outreach /21 Beyond Lambda - Why Coupled Quintessence? Questions of Coupled Quintessence Need a generalised code to test any given coupled quintessence model and allow comparison with observations We are developing code, PYESSENCE, to do this Background evolution of a model must match observations (CMB, SN data) If background satisfies this, is the perturbed model stable (under what range of couplings/no. of fields etc.)? If perturbation are stable do they match observations from large scale structure surveys e.g. BOSS, DES, eboss, DESI, Euclid?

18 Alex Leithes (QMUL) Cosmology Beyond the Standard Model QMUL Outreach /21 PYESSENCE code - Work to date Work to date For first time plotted evolution of stable perturbations to this 2 fluid, 2 field, sum of exponentials model, for a point in coupling constant space, in fourier space. For the plot below k = H 0

19 Alex Leithes (QMUL) Cosmology Beyond the Standard Model QMUL Outreach /21 Results and future work Results and future work Forthcoming paper to present these results in full, with maps of stable regions of couplings parameter space, and release PYESSENCE code for community Constrain models through stability Constrain models through comparison with LSS surveys (Euclid etc.) and again...

20 Alex Leithes (QMUL) Cosmology Beyond the Standard Model QMUL Outreach /21 Results and future work... got to travel to Sicily to talk about my work... :)

21 Alex Leithes (QMUL) Cosmology Beyond the Standard Model QMUL Outreach /21 Results and future work...and win a prize! :D Thank you!