English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We provide a detailed theoretical analysis of the adiabatic evolution ofdegenerate open quantum systems, where the dynamics is induced bytime-dependent fluctuating loop paths in control parameter space. For weaksystem-bath coupling, the fluctuations around a deterministic base path obeyGaussian statistics, where we assume that the quantum adiabatic theorem is alsosatisfied for fluctuating paths. We show that universal non-Abelian geometricdephasing (NAGD) contributions are contained in the fluctuation-averagedevolution operator. This operator plays a key role in all experimentalprotocols proposed in this work for the detection of NAGD. In particular, weformulate interference measurements providing full access to NAGD. Apart from afactor due to the dynamic phase and its fluctuations, the averaged evolutionoperator contains the averaged Berry matrix. A polar decomposition of thisnon-unitary matrix into the product of a unitary, $V$, and a positivesemi-definite Hermitian matrix, $R$, reveals the physics of the NAGDcontributions. Unlike the conventional dynamic dephasing rate, the NAGDeigenrates encoded by $R$ depend on the loop orientation sense and, inparticular, change sign under a reversal of the direction. A negative rate thenimplies amplification of coherences as compared to the ones when only dynamicdephasing is present. The non-Abelian character of geometric dephasing isrooted in the non-commutativity of $V$ and $R$ and causes smoking-gunsignatures in interference experiments. We also clarify why systems subject totopological protection do not show geometric dephasing. Without fullprotection, however, geometric dephasing can arise and has to be taken intoaccount. As concrete application, we propose spin-echo NAGD detection protocolsfor modified Majorana braiding setups.

Non-Abelian Berry phase for open quantum systems: Topological protection vs geometric dephasing