Quantum and classical gravity in low-energy quantum systems (2nd BridgeQG Training School)

Europe/Belgrade
Aleksandra Gocanin, Nikola Konjik
Description

Belgrade Scavenger Hunt: Belgrade Scavenger Hunt

The goal of this physics school is to offer master and Ph.D. students from the field of experimental and theoretical physics as well as mathematics and philosophy a coherent introduction to the subject of quantum gravity in low energy quantum systems from both theoretical and experimental perspectives. 

The participants will receive training in the theoretical description of quantum system under the influence of gravity and how to predict observable signatures. They will learn how specific experimental setups can be used to test the theoretical predictions. This education equips the participants with the skills to bridge the gap between theory and experiment in the field of the interplay between quantum systems and classical and quantum gravity research in the future.

This is the second of a series of Training Schools organized by the European COST Action CA23130 - BridgeQG: Bridging high and low energies in search of quantum gravity (https://web.infn.it/BridgeQG).

While the focus of the first training school was on the high-energy aspects of the BridgeQG research topics, the focus of this training school will be on the low-energy aspects.

A third school will cover the combination of the two branches.

The school consists of four main lectures, which are accompanied by tutorial classes. In addition there will be an introductory short lecture on quantum gravity phenomenology, and a concluding short lecture. Lecture notes will be published after the school.

Lecturers and topics

Časlav Brukner: Quantum clocks and Quantum Reference Frames for Quantum Gravity

Rainer Kaltenbaek: Testing Quantum Physics in Space

Sofia Qvarfort: Quantum Metrology and the Standard Quantum Limit

In these lectures, we will cover quantum and classical Fisher information as a tool for quantifying the sensitivity of quantum systems. We will then also look at the fundamental limits of positions measurements, which are key for e.g. gravitational wave measurements, and which leads to the Standard Quantum Limit. 

Benjamin Stickler: Quantum control of optically trapped nanoparticles

Controlling the quantum mechanical motion of dielectric nanoscale to microscale particles requires a detailed understanding of their dynamics in the presence of electromagnetic fields and ambient environments. In this seminar we will discuss the theoretical description of how nanoparticles interact with laser light and how this coupling can be used to optically trap, control, and monitor their motion.
 

Simone Manti: Testing quantum gravity with underground experiments

Quantum mechanics provides an extraordinarily successful description of microscopic phenomena, yet fundamental questions remain open. Among the most important are the origin of wave function collapse, embodied in the measurement problem, and the exact validity of the Pauli Exclusion Principle, one of the cornerstones of quantum theory. In this talk, I will present a program of precision experiments conducted at the underground laboratories of INFN Laboratori Nazionali del Gran Sasso, designed to probe possible deviations from standard quantum mechanics in ultra-low-background conditions. Using state-of-the-art radiation detectors, we search for two classes of rare phenomena: spontaneous electromagnetic emission predicted by dynamical collapse models, proposed as physically motivated solutions to the measurement problem and potentially connected to gravity, and Pauli-forbidden atomic transitions, which would signal violations of fermionic quantum statistics. I will discuss recent experimental results placing increasingly stringent bounds on Continuous Spontaneous Localization and related collapse scenarios, including tests motivated by gravity-induced collapse frameworks. I will also present the latest advances of the VIP Collaboration in high-sensitivity searches for possible violations of the Pauli Exclusion Principle. Together, these studies open a unique experimental window on quantum foundations, connecting precision measurements, underground rare-event searches, and emerging ideas at the interface between quantum theory and gravity.

Djordje Minić: Quantum Spacetime, Quantum Gravity, and Gravitized Quantum Theory, based on https://arxiv.org/pdf/2604.19418 and https://arxiv.org/abs/2407.06207

Lin-Qing Chen: Theoretical Aspects for Low-energy Tests of Quantum Gravity

Recent experimental advances have made low-energy gravity a promising regime for probing the quantum nature of gravity. In this lecture, I will discuss what it means to verify the quantumness of gravity and why this question might become experimentally accessible in the foreseeable future. A canonical example is the gravity-induced entanglement protocol, whose interpretation has generated important debates and subtleties in recent years.

I will then introduce the theoretical framework suited to making predictions in this regime. I will first start from electromagnetism, then turn to linearized gravity and show how one can solve for the quantum state of a quantum source and its gravitational field, using the Schrödinger representation and the wave functional of the gravitational field. Finally, I will briefly describe recent efforts and directions toward developing new experimental protocols.


About COST Action CA23130 BridgeQG

Recent advances in both high-energy astrophysics and high-precision table-top experiments are pushing our capability to test nature in regimes where gravity meets quantum physics. Astrophysical observations are now potentially sensitive to tiny residual effects of Planck-scale physics, while table-top experiments are reaching the precision needed to test the interplay between gravity and quantum systems at ultra-low energies. Investigations of these regimes, in particular once they are combined, will provide important clues towards the understanding of the full-fledged theory of quantum gravity.

The main aim of the Action is to bring together scientists with a variety of complementary expertise: theorists working on quantum gravity or the interplay between gravity and quantum physics with quantum information and quantum optics tools, and experimentalists involved in astrophysical searches for quantum gravity, or investigating the effects of gravitational interactions on quantum systems. The resulting interdisciplinary collaboration will develop a common language and a shared framework which will boost investigations at the interface between high-energy quantum gravity and quantum aspects of gravity in the weak-field regime. The Action will also facilitate cross-disciplinary training and exposure of young scientists to different communities with a common goal, serving as a career accelerator. The synergy within this newly-formed community will be essential to systematically search for quantum gravity on all scales, and possibly find the first signatures of new physics.

 

Local Organizing Committee: 

Marija Dimitrijević Ćirić, Nikola Konjik, Aleksandra Gočanin, Ivana Đorđević, Dušan Đorđević, Jovan Potrebić

Scientific Organizing Committee: 

J. Bolmont (LPNHE, Paris, France), L.-Q. Chen (Vienna U, Austria), C. O. Curceanu (INFN-LNF, Italy),  A. Domi (ECAP Erlangen-Nürnberg U, Germany), M. Fadel (ETH Zürich, Switzerland), T. Galley (IQOQI Vienna, Austria), F. Giacomini (ETH Zürich, Switzerland), G. Gubitosi (U Napoli Federico II, Italy), F. Mercati (Burgos U, Spain), A. Platania (Graz University, Austria), C. Pfeifer (ZARM, Bremen U, Germany), G. Rosati (U Cagliari, Italy), D. Staicova (INRNE, Bulgaria), J. Strišković (Osijek U, Croatia), T. Terzic (Rijeka U, Croatia), M. Tórtola (Valencia U, Spain)

Acknowledegments

This conference is supported by COST (European Cooperation in Science and Technology). COST is a funding agency for research and innovation networks. COST Actions help connect research initiatives across Europe and enable scientists to grow their ideas by sharing them with their peers. This boosts their research, career and innovation.

 

CA23130 – Bridging high and low energies in search of quantum gravity (BridgeQG)         

      

Registration
Registration for lecturers
    • 8:30 AM 9:00 AM
      Registration 30m
    • 9:00 AM 11:00 AM
      Brukner: Quantum Reference Frames 1

      Spaker

      Convener: Časlav Brukner
    • 11:00 AM 11:30 AM
      Coffee break 30m
    • 11:30 AM 1:30 PM
      Kaltenbaek: Testing Quantum Physics in Space 1
      Convener: Rainer Kaltenbaek
    • 1:30 PM 3:30 PM
      Lunch break
    • 3:30 PM 5:30 PM
      Quantum Spacetime, Quantum Gravity, and Gravitized Quantum Theory
      Convener: Đorđe Minić
    • 5:30 PM 6:00 PM
      Coffee break 30m
    • 6:00 PM 8:00 PM
      Student talks: Part 1
    • 9:00 AM 11:00 AM
      Kaltenbaek: Testing Quantum Physics in Space 2
      Convener: Rainer Kaltenbaek
    • 11:00 AM 11:30 AM
      Coffee break 30m
    • 11:30 AM 1:30 PM
      Qvarfort: Quantum Metrology and the Standard Quantum Limit 1
      Convener: Sofia Qvarfort
    • 1:30 PM 3:30 PM
      Lunch break
    • 3:30 PM 5:30 PM
      Brukner: Quantum Reference Frames 2

      Spaker

      Convener: Časlav Brukner
    • 5:30 PM 8:00 PM
      Free time 2h 30m
    • 8:00 PM 12:00 AM
      School dinner 4h
    • 9:00 AM 11:00 AM
      Qvarfort: Quantum Metrology and the Standard Quantum Limit 2
      Convener: Sofia Qvarfort
    • 11:00 AM 11:30 AM
      Coffee break 30m
    • 11:30 AM 1:30 PM
      Brukner: Quantum Reference Frames tutorial

      Spaker

      Convener: Časlav Brukner
    • 1:30 PM 3:30 PM
      Lunch break
    • 3:30 PM 5:30 PM
      Kaltenbaek: Testing Quantum Physics in Space: Tutorial
      Convener: Rainer Kaltenbaek
    • 5:30 PM 6:00 PM
      Coffee break 30m
    • 6:00 PM 8:00 PM
      Stickler: Quantum control of optically trapped nanoparticles 1
      Convener: Benjamin Stickler
    • 9:00 AM 11:00 AM
      Qvarfort: Quantum Metrology and the Standard Quantum Limit tutorial
      Convener: Sofia Qvarfort
    • 11:00 AM 12:00 PM
      Student talks: Part 2
    • 12:00 PM 1:00 PM
      Lunch break
    • 1:00 PM 3:00 PM
      Stickler: Quantum control of optically trapped nanoparticles 2
      Convener: Benjamin Stickler
    • 3:00 PM 3:30 PM
      Free time 30m
    • 3:30 PM 8:00 PM
      Lunch break: Sport activities and BBQ
    • 9:00 AM 11:00 AM
      Stickler: Quantum control of optically trapped nanoparticles - tutorial
      Convener: Benjamin Stickler
    • 11:00 AM 11:30 AM
      Coffee break 30m
    • 11:30 AM 1:30 PM
      Manti: Testing quantum gravity with underground experiments
      Convener: Simone Manti
    • 1:30 PM 3:30 PM
      Lunch break
    • 3:30 PM 5:30 PM
      Chen: Theoretical aspects of tabletop tests of quantum gravity
      Convener: Lin-Qing Chen
    • 5:30 PM 6:30 PM
      Discussion time 1h
    • 6:30 PM 8:00 PM
      Lunch break: Farewell cocktail