Seminarium Zakładu Fizyki Teoretycznej

Modifying the geometry of the Universe

The nature of dark energy is the biggest problem in cosmology. But the answer may not be very different to what most cosmologists assume. General relativity is not a complete theory. It leaves many important questions unanswered, including the nature of gravitational energy. This is directly relevant to an important observational fact: the Universe is a very inhomogeneous cosmic web on the small scales on which general relativity is actually tested.

The Flavor of UV Physics

New physics not far above the TeV scale should leave a pattern of virtual effects in observables at lower energies. What do these effects tell us about the structure of a UV theory? We will address this question by considering the Standard Model as an Effective Field Theory, which allows us to relate physics at different energy scales through the renormalization group. I will show how to deduce possible features of a UV theory by combining top-quark observables at the LHC with bottom observables at the flavor factories.


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Quantum Simulators of Lattice Gauge Theories

In my talk I present a review of recent developments in the area of quantum simulators (QS) of lattice gauge theories. I will start with explaining what quantum simulators are, and will discuss various platform for and paradigmatic examples of QS. I will spend some time to explain how can one realize artificial static gauge fields in systems of trapped ultracold atoms, atoms in optical lattices and in synthetic dimensions. Finally, I will focus on  quantum simulators of lattice gauge theories and dynamical gauge fields, and present four examples:

Singularity theorems: A critical appraisal

The 2020 Nobel prize in Physics has revived the interest in the singularity theorems and, in particular, in the Penrose theorem published in 1965. In this talk I will briefly review the main ideas behind the theorems and I will proceed to an evaluation of their hypotheses and implications. I will try to dispel some common misconceptions about the theorems and their conclusions, as well as to convey some  of their rarely mentioned consequences. Several examples will be used for illustrative purposes.


Wojciech Kamiński (IFT FUW)

Lattice gauge theories and cold atomic mixtures

In the fundamental laws of physics, gauge fields mediate the interaction between charged particles. An example is quantum electrodynamics—the theory of electrons interacting with the electromagnetic field—based on U(1) gauge symmetry. Solving such gauge theories is in general a hard problem for classical computational techniques. While quantum computers suggest a way forward, it is difficult to build large-scale digital quantum devices required for complex simulations. In this talk, I will present our work on analog quantum simulators of a U(1) gauge theory in one spatial dimension.

Testing quantum gravity and quantum gravity phenomenology

In my talk I will first briefly describe quantum gravity and characterize quantum gravity effects. Then I will argue that although it does not seem

feasible to observe quantum gravity effects directly, we could, or will be able in a near future, experimentally test deviations from the standard

physics of the quantum gravitational origin. I will present some effects of this kind and argue that quantum gravity phenomenology is possible

and can be fruitfully explored.



Entanglement by identity, or interaction without ever touching

What is interaction and when does it occur? Intuition suggests that the necessary condition for the interaction of independently created particles is their direct touch or contact through physical force carriers. In quantum mechanics, the result of the interaction is entanglement — the appearance of non-classical correlations in the system. It seems that quantum theory allows entanglement of independent particles without any contact. The fundamental identity of particles of the same kind is responsible for this phenomenon.