Primordial black holes, de Sitter space and quantum tests of gravity

11 Feb 2019, 14:00 → 13 Feb 2019, 17:30 Europe/Berlin

Bldg. 2a, SR 2 (DESY Hamburg)

This workshop brings together theorists and experimentalists who work on recent developments in cosmology, quantum theory and gravitational physics. The main topics are

• Primordial black holes and gravitational waves
• Quantum mechanical tests of gravity
• de Sitter space and dark energy

The goal of the workshop is to present new ideas and to stimulate discussions across the different research areas.

 

Invited speakers include

• Markus Aspelmeyer (Vienna)
• Matthias Bartelmann (Heidelberg) 
• Alessio Belenchia (Belfast) 
• Sougato Bose (London)
• Bernard Carr (London) 
• Valerie Domcke (DESY) 
• Georgi Dvali (Munich) 
• Arthur Hebecker (Heidelberg) 
• Florian Kühnel (Stockholm) 
• Kyohei Mukaida (DESY) 
• Marco Peloso (Padua) 
• Serge Reynaud (Paris)
• Roman Schnabel (Hamburg)
• Alexander Westphal (DESY)  

 

Organizing committee

Markus Aspelmeyer, Wilfried Buchmüller, Karsten Danzmann, Georgi Dvali, Elisabetta Gallo, Jürgen Schmitt, Roman Schnabel 

 

Monday 11 February

14:00 → 14:30 Registration, welcome

14:30 → 14:32 CHAIR: Juergen Schmitt

14:32 → 15:30 Primordial Black Holes - Formation and Observational Constraints

Speaker: Florian Kühnel

Slides Kuhnel,_Florian_-_Primordial_black_holes,_de_Sitter_space_and_quantum_tests_of_gravity_-_DESY_-_February_2019_-_shortened.pdf

15:30 → 16:00 Coffee break

16:00 → 17:00 Primordial Black Holes from Inflation and Their Implications

Speaker: Kyohei Mukaida

Slides kmukaida.pdf

17:00 → 18:00 Sourced density perturbations and gravitational waves (GW) from inflation, and GW signatures of Primordial Black Holes

Speaker: Marco Peloso

Slides DESY19-peloso.pdf

18:30 → 20:00 Reception

Tuesday 12 February

09:00 → 09:02 CHAIR: Juergen Schmitt

09:02 → 10:00 Gravitational waves and primordial black holes from cosmic inflation

Speaker: Valerie Domcke

Slides DESY_PBH_workshop_domcke.pdf

10:00 → 10:30 Coffee break

10:30 → 11:30 Primordial black holes: Linking Microphysics and Macrophysics

Black holes could span 60 decades of mass - from the Planck scale (10-5g) to the cosmological scale (1022Mo) - and therefore provide an important link between microphysics and macrophysics. In the macroscopic domain, attention has recently turned to the possibility that primordial black holes (i.e. those formed in the early universe) could provide the dark matter or the black-hole mergers detected by LIGO or even some features of cosmic structure. In the microscopic domain, primordial black holes lighter than the Earth would have a Hawking temperature exceeding that of the cosmic microwave background, so that quantum effects are important. Such quantum black holes span the lower 30 decades of mass and provide a unique probe of the early universe and high energy physics. The micro-macro link is most striking at the Planck scale, with Planckian black holes likely to play a key role in quantum gravity. This raises the question of what happens to relativity theory as one approaches the Planck scale from above (eg. the Schwarzschild radius) and to quantum theory as one approaches it from below (eg. the Compton radius). It is argued that there should be a smooth transition between these two scales, corresponding to a unified Compton-Schwarzschild expression. In this case, there may also be a link between elementary particles and sub-Planckian black holes. It is also argued that the duality between the Compton and Schwarzschild scales should be maintained if the number of spatial dimensions increases, which has important implications for the observability of black holes in accelerators.

Speaker: Bernard Carr

Slides Carr-DESY-2019.pdf

11:30 → 12:30 Quantum Tests of Gravity: State of the Play, Prospects and Experimental Challenges

Speaker: Markus Aspelmeyer

12:30 → 14:00 Lunch

14:00 → 14:02 CHAIR: Elisabetta Gallo

14:02 → 15:00 Quantum Superposition of Massive Objects and the Quantization of Gravity

Speaker: Alessio Belenchia

Slides DESY-talk2019Belenchia.pdf

15:00 → 15:30 Coffee break

15:30 → 16:30 Transferring two massive mirrors into a single quantum object

When a single quantum object decays into two, the new objects show quantum entanglement. For the experimental demonstration of this entanglement, a large number of identical decays need to be available and specific measurements on the new objects performed. This talk considers the opposite direction of evolution and describes an experiment, in which two laser mirrors that are suspended as pendulums might be transferred to a single quantum object. The unification goes hand in hand with the mirrors losing the realism of their individual positions and momenta. Here, the definition of (local) realism is according to the 1935-discussion by Einstein, Podolsky and Rosen. In the envisioned experiment, the two mirrors will have masses of about 100g and are located close to each other such that they sense the mutual gravitational potential. If successful the experiment might be a probe system for Newtonian quantum gravity theories.

Speaker: Roman Schnabel

Slides 190212_AdW_Hamburg_Schnabel.pdf

16:30 → 17:30 Is the Moon there when nobody looks?

Speaker: Serge Reynaud

Slides Hamburg19isthemoonthere.pdf

Wednesday 13 February

09:00 → 09:02 CHAIR: Karsten Danzmann

09:02 → 10:00 Quantum Coherences with Gravity

Speaker: Myungshik Kim (Imperial College London)

10:00 → 10:30 Coffee break

10:30 → 11:30 Evidence for the history of cosmic expansion

The cosmic expansion function, quantifying how the relative cosmic expansion rate developed in cosmic history, is one of two central and (almost) directly observable properties of our Universe. From a theoretical point of view, the expansion function is determined by the time evolution of all forms of matter and energy density in the Universe. Empirically, it enters into all distance measures and into the growth function describing the evolution of cosmic structures. I will first summarize the empirical information available on the expansion function and then show that the expansion function is tightly contrained without the need to specify any cosmological model. Adopting a metric theory of gravity and the usual symmetries of spatial isotropy and homogeneity suffice to determine the expansion function quite precisely. With little further assumptions, also the growth function is empirically tightly constrained. Such empirical limits on these two functions which are independent of any particular cosmological model, are to a large degree also valid for alternative theories of gravity.

Speaker: Matthias Bartelmann

Slides Bartelmann.pdf

11:30 → 12:30 de Sitter Space and String Theory

Speaker: Alexander Westphal

Slides DESY_Feb_2019_Westphal.pdf

12:30 → 14:00 Lunch

14:00 → 14:02 CHAIR: Wilfried Buchmuller

14:02 → 15:00 dS Swampland conjectures and KKLT

Speaker: Arthur Hebecker

Slides Hebecker_slides.pdf

15:00 → 16:00 Secrets of de Sitter and phenomenological implications

Speaker: Georgi Dvali

16:00 → 16:30 Coffee closing