CQD > talk

CQD Special Seminar

13. April 2010 17:30

HS 1, Kirchhoff-Institut für Physik, Im Neuenheimer Feld 227

Inauguration ceremony with Public lecture: Time and Einstein in the 21st century

Prof. Bill Phillips
National Institute of Standards and Technology, Gaithersburg, USA


Public Evening Lecture

at the occasion of the inauguration of the

Center for Quantum Dynamics of the Ruprecht-Karl University Heidelberg

“Time and Einstein in the 21st century”

Prof. Bill Phillips



Abstract: At the beginning of the 20th century Einstein changed the way we think about Nature. At the beginning of the 21st century Einstein's thinking is shaping one of the key scientific and technological wonders of contemporary life: atomic clocks, the best timekeepers ever made. Such super-accurate clocks are essential to industry, commerce, and science; they are the heart of the Satellite Navigation System that guides cars, airplanes, and hikers to their destinations. Today, atomic clocks are still being improved, using atoms cooled to incredibly low temperatures. Atomic gases reach temperatures less than a billionth of a degree above Absolute Zero,without freezing. Such atoms enable clocks accurate to better than a second in 80 million years as well as both using and testing some of Einstein's strangest predictions.


Programme


16:00 - 17:30 hours:
Poster presentation of the groups of the Center for Quantum Dynamics in the Foyer of the Kirchhoff Institute.


17:30 - 19:00 hours:
Inauguration Ceremony by representatives of the University (Dean of the Department of Physics and Astronomy, Prof. Christian Enss, and Director of the CQD and Director of the Physics Institute, Prof. Matthias Weidemüller).

Lecture by Prof. Bill Phillips
 
afterwards:
Get-together at the Foyer of the Kirchhoff Institute.
 

up
CQD Colloquium

12. November 2025 16:30 Uhr

INF 226, K1-3 (Goldbox)

tba

Dr Rob Smith, University of Oxford

 PreTalk: Andreea Oros, KIP, Heidelberg University

CQD Special Seminar

7. November 2025 13:30 Uhr

INF 226, K1-3 (Goldbox)

Scale invariance and universal probability distribution of an order parameter across a continuous phase transition

Prof David Clément , Institut d'Optique Graduate School, Laboratoire Charles Fabry, France

Scale invariance lies at the foundation of modern statistical physics and underpins the description of continuous phase transitions. Its most striking manifestation is the universal probability distribution function (PDF) of the order parameter, which encapsulates the complete statistical structure of critical fluctuations—beyond what traditional quantities such as averages or critical exponents can reveal. However, this universal distribution is exceptionally challenging to measure, as it reflects the non-Gaussian and scale-invariant nature of critical fluctuations.

We will report on the experimental study of the statistics of the condensate order parameter across the superfluid–Mott transition in a gas of 3D lattice bosons, making use of single-atom-resolved detection in momentum space [1]. First, we observe non-Gaussian statistics of the order parameter near the transition, distinguished by non-zero and oscillating high-order cumulants [2]. We provide direct experimental evidence that these oscillations are universal. Second, crossing the Mott transition for various entropies and collapsing the cumulant oscillations, we obtain the non-universal coefficients required to reconstruct the universal PDF [3]. Finally, this universal scaling function determined experimentally is shown to yield algebraic scaling laws whose exponents are consistent with the critical exponents of the (expected) 3D XY universality class.

 

contact
Prof. Dr. M. Weidemüller
Physikalisches Institut
Im Neuenheimer Feld 226
69120 Heidelberg
 
06221-54 19470
Ferman Alkasari