Experimental Observation of Decoherence

Schlosshauer-Selbach, Andreas M

Carsten Henkel, Mathias Nest, P. Domokos +1 more

We propose a new way to observe environment-induced spatial decoherence of massive objects. The method is designed to work with a wide variety of masses from the atomic scale, to nano-fabricated structures. It is based on the fact that spatial decoherence can lead to the build-up of coherences between energy eigenstates. These can be observed as oscillations in a balanced optical interferometer. We discuss the experimental feasibility of the method, and explore the possibility of differentiating between `pure' decoherence and that coinciding with energy transfer and heating.

Kevin ELLIS ANDERSON

This deposit contains the paper “Constraints and Observable Limits of Emergent Decoherence in Variational Dissipative–Conservative Dynamics” by Kevin Ellis Anderson. The paper analyses theoretical and observational constraints applicable to emergent decoherence models arising from variational dissipative–conservative partial differential equation dynamics. Rather than proposing new experimental predictions, the work focuses on identifying limits of applicability, assumptions underlying reduced descriptions, and compatibility with existing experimental evidence for quantum coherence. Constraints are derived from structural features of the framework, coarse-graining assumptions, and established experimental bounds on coherence times in interferometric and mesoscopic systems. Parameter regimes in which emergent decoherence is negligible, invalid, or inconsistent are explicitly identified, together with conditions under which the framework would fail or be ruled out in principle. This analysis establishes clear boundaries for the use of variational dissipative–conservative dynamics as a model of decoherence-like behaviour, strengthening the conceptual consistency of the framework by preventing overextension beyond its justified domain.

J. M. Raimond

F. Chiarello, E Paladino, Maria Gabriella Castellano +4 more

A particular superconducting quantum interference device (SQUID) qubit, namely the double SQUID qubit, can be manipulated by rapidly modifying its potential with the application of fast flux pulses.In this system we observe coherent oscillations exhibiting non-exponential decay, indicating an unconventional decoherence mechanism.Moreover, via tuning the qubit in different conditions (different oscillation frequencies) by changing the pulse height, we observe a crossover between two distinct decoherence regimes and the existence of an 'optimal' point where the qubit is only weakly sensitive to intrinsic noise.We find that this behavior is in agreement with a model considering the decoherence caused essentially by low-frequency noise contributions, and we discuss the experimental results and possible issues.

Maximilian Schlosshauer