Effects of entanglement between inflaton and Higgs (Stockholm University Collaboration).
Entanglement during inflation from kinetic mixing in action (YITP Collaboration).
Comparison of non-gaussianities produced by inflation with entanglement and multi-field inflation (UC Davis Collaboration).
Theories and Models of the Dark Sector: Constraining dark matter, dark energy and modified gravity models (CEICO Collaboration).
Alleviating Tension in H0 Measurement with Minimal Theory of Massive Gravity (YITP Collaboration).
Contact Me
E-mail:
nbolis@ucdavis.edu
bolis@fzu.cz
About Me
Past:
Graduated from Bryn Mawr College, PA.
Degree: B.A. (June 2010).
Major: Physics.
Minor: Japanese.
Graduated from University of California Davis, CA.
Degree: Masters (Oct 2014) and PhD (July 2017).
Research Area: Theoretical Cosmology -- Inflation.
Adrvisor: Dr. Andreas Albrecht.
Present:
Post Doctoral Researcher at CEICO (Central European Institute for Cosmology and Fundamental Physics), Prague, CZ.
Supervisor: Dr. Costantinos Skordis.
Research Area: Theoretical Cosmology -- Inflation, Constraining Dark Matter, Dark Energy and Modified Gravity.
Future:
Looking for Post Doc positions for Fall 2019.
Research Interests
I find cosmology fascinating because it lies at the intersection of many fundamental questions re-
lated to both particle physics and the origin of our Universe and is able to address them in a novel and
concrete way. I am currently in the first year of my postdoc at CEICO (Central European Institute of
Cosmology and Fundamental Physics, Prague) working with Dr. Constantinos Skordis. I was awarded my PhD
in July, 2017 from the University of California, Davis where I worked for Dr. Andreas Albrecht. My
research in theoretical cosmology in graduate school mainly focused on inflation, in particular, the ob-
servational effects of entanglement during inflation. Since then, I have expanded my horizons and have
also begun to work on several projects on constraining dark matter, dark energy and modified gravity.
Entanglement during inflation – Inflation is currently the most well supported and well motivated
paradigm to describe the history of the very early universe. In the standard scenario the inflaton starts
in its ground state: the Bunch Davies vacuum. However, in light of the fact that we do not fully understand
short distance physics, it is still important to consider the possibility of small deviations from a
Bunch Davies initial state. In addition to this, most extensions to the Standard Model, such as String
Theory, allow for a number of light fields. This fact has motivated many to look into multi-field inflation.
I chose to explore an alternate scenario, entanglement between the inflaton perturbations with other
spectator fields. Evidence of entanglement during inflation would not only suggest a small deviation
from the BD vacuum but may also indicate finite inflation. We used Schro ̈dinger Picture Quantum
Field Theory which is ideal for exploring the phase space of states with small deviations from BD. I
constructed two entanglement models, the first had the inflaton fluctuations entangled with another
spectator scalar field [1]. The second model consisted of entanglement between the inflaton perturbations
and the tensor fluctuations [2]. The first model would be more relevant within the context of a
framework that predicts multiple scalar fields while the second model does not require any extra fields.
Both models induce some interesting behavior, including small oscillations in the angular power spectrum.
These features can be used to constrain entanglement with current and upcoming cosmological
data. I was invited to give six talks on this work and have embarked on several followup projects on
related topics. These include calculating the bispectrum for the scalar-scalar entanglement scenario
to ascertain what non-Gaussianity signal one might expect from such models (upcoming paper), and
trying to map the effect of entanglement to a kinetic mixing action. One of the motivations for these
two projects is to quantify the observational differences between entanglement amongst multiple scalar
fields and multi-field inflation.
Alleviating Tension in H0 Measurement– Last spring I began work on massive gravity in collaboration
with Dr. Antonio De Felice and Dr. Shinji Mukuyama from Yukawa Institute of Theoretical Physics, Kyoto. We explore the possibility
that certain solutions of the Minimal Theory of Massive Gravity ([3, 4]) can help alleviate the tension between the Supernovae measurement
of the Hubble parameter H0 [5] and the Planck measurement [6]. To achieve this, we do a Chi-Squared fit of the Integrated-Sachs-Wolfe
cross galaxy angular power spectrum (ClISW,g) with cross ISW-galaxy data sets (upcoming paper).
Constraining DM, DE and Modified Gravity Theories– As a postdoc at CEICO, I joined the Theories and Models of the Dark Sector: Dark Matter, Dark Energy and Gravity project headed by my supervisor Dr. Skordis and funded by the ERC Consolidator Grant. The main goal of this project is to systematically constrain models of dark matter (DM), dark energy (DE) and modified gravity by using both cosmological and solar system data. Understanding the nature of dark matter and dark energy is one of the most interesting questions we face in cosmology today. An important part of this is constrain- ing theories of modified gravity capable of mimicking the effect of DM or DE. My role in this project, so far, has been to constrain modified gravity theories with a screening mechanism such as, Hordeski theories. The screening for some of these theories may not be perfect; therefore, it is important to check for small deviations from General Relativity on small scales. The departures from GR can be encoded by parameters in the Post-Parametrized-Newtonian-Vainshtein (PPNV) formalism [7] which can help us test these theories with solar system data.
References
[1] A. Albrecht, N. Bolis and R. Holman, Cosmological Consequences of Initial State Entanglement, JHEP 11 (2014) 093, [1408.6859].
[2] N. Bolis, A. Albrecht and R. Holman, Modifications to Cosmological Power Spectra from Scalar-Tensor Entanglement and their Observational Consequences, JCAP 1612 (2016) 011, [1605.01008].
[3] A. De Felice and S. Mukohyama, Minimal theory of massive gravity, Phys. Lett. B752 (2016) 302–305, [1506.01594].
[4] A. De Felice and S. Mukohyama, Graviton mass might reduce tension between early and late time cosmological data, Phys. Rev. Lett. 118 (2017) 091104, [1607.03368].
[5] J. L. Bernal, L. Verde and A. G. Riess, The trouble with H0, JCAP 1610 (2016) 019, [1607.05617].
[6] Planck collaboration, P. A. R. Ade et al., Planck 2015 results. XIII. Cosmological parameters, Astron. Astrophys. 594 (2016) A13, [1502.01589].
[7] A. Padilla and P. M. Saffin, Classical Duals, Legendre Transforms and the Vainshtein Mechanism, JHEP 07 (2012) 122, [1204.1352].
"Cosmological Consequences of Initial State Entanglement". Andreas Albrecht, Nadia Bolis, R. Holman, JHEP 1411 (2014) 093, arXiv:1408.6859.
"Modifications to Cosmological Power Spectra from Scalar-Tensor Entanglement and their Observational Consequences". Nadia Bolis, Andreas Albrecht, R. Holman, JCAP 1612 (2016) 12, arXiv:1605.01008.
" Probing extra dimensions with gravitational and electromagnetic signals from compact mergers" Luca Visinelli, Nadia Bolis, Sunny Vagnozzi, (Nov. 2017), arXiv:1711.06628.
Sep. 2015:"Effects of Entanglement during Inflation on Cosmological Observable" (Talk). Conference: Cosmo Cruise 2015 , Barcelona, Spain.
Jun. 2016:"Observational Consequences of Scalar-Tensor Entanglement During Inflation" (Poster). Summer School: ICTP Cosmology Summer School, Trieste, Italy.
Aug. 2016:"Observational Consequences of Scalar-Tensor Entanglement During Inflation" (Talk). Conference: COSMO’16, Ann Arbor, MI, USA.
Sep. 2016:"Observational Consequences of Scalar-Tensor Entanglement During Inflation" (Invited Talk), Conference: VARCOSMOFUN’16, Szczecin, Poland. Invited by: Dr. Sugumi Kanno.
Oct. 2017:"Un-entangling the Universe" (Invited Talk). Colloquium: Oskar Klein Centre Colloquium, Oskar Klein Centre, Stockholm, Sweden. Invited by: Dr. Katherine Freese.
Oct. 2017:"Entanglement and Non-Gaussianity" (Invited Talk). Seminar: YITP Cosmology Seminar, Yukawa Institute for Theoretical Physics, Kyoto, Japan. Invited by: Dr. Antonio De Felice.
Oct. 2017:"Entanglement and Non-Gaussianity" (Invited Talk). Seminar: Kobe University Cosmology Seminar, Kobe University,Kobe, Japan. Invited by: Dr. Jiro Soda.
Dec. 2017:"Entanglement and Non-Gaussianity" (Invited Talk). Seminar: University of the Basque Country Seminar, University of the Basque Country, Bilbao, Spain. Invited by: Dr. Sugumi Kanno.
Jan. 2018:"Entanglement during Inflation and Signals of Non-Gaussianity" (Invited Talk). Seminar: University of California Davis Cosmology Seminar, UC Davis, Davis, USA. Invited by: Dr. Andreas Albrecht.
