| 1. |
- Ferreiros, Yago, et al.
(författare)
-
Mixed Axial-Torsional Anomaly in Weyl Semimetals
- 2019
-
Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 122:5
-
Tidskriftsartikel (refereegranskat)abstract
- We show that Weyl semimetals exhibit a mixed axial-torsional anomaly in the presence of axial torsion, a concept exclusive of these materials with no known natural fundamental interpretation in terms of the geometry of spacetime. This anomaly implies a nonconservation of the axial current - the difference in the current of left- and right-handed chiral fermions - when the torsion of the spacetime in which the Weyl fermions move couples with opposite sign to different chiralities. The anomaly is activated by driving transverse sound waves through a Weyl semimetal with a spatially varying tilted dispersion, which can be engineered by applying strain. This leads to a sizable alternating current in the presence of a magnetic field that provides a clear-cut experimental signature of our predictions.
|
|
| 2. |
- Andersson, Birger, et al.
(författare)
-
Towards a common ontology for business models
- 2006
-
Ingår i: CEUR Workshop Proceedings.
-
Konferensbidrag (refereegranskat)abstract
- To create an understanding of enterprises and the ways they do business, a starting point could be to identify the main actors and the values transferred between them. Business models are created in order to make clear who the business actors are in a business case and to make their relations explicit. The relations are formulated in terms of values exchanged between the actors. The purpose of the work reported in this paper is to create a better understanding of business models by identifying basic notions used in such models. It does so by constructing a common ontology based on three established business model ontologies: e3-value, REA, and BMO. By means of a careful analysis of these ontologies a conceptual schema is created that defines the common concepts. An example is worked out that explains how the common ontology should be understood.
|
|
| 3. |
|
|
| 4. |
- Fleckenstein, Christoph, et al.
(författare)
-
Non-Hermitian topology in monitored quantum circuits
- 2022
-
Ingår i: Physical Review Research. - : American Physical Society (APS). - 2643-1564. ; 4:3
-
Tidskriftsartikel (refereegranskat)abstract
- We demonstrate that genuinely non-Hermitian topological phases and corresponding topological phase transitions can be naturally realized in monitored quantum circuits, exemplified by the paradigmatic non-Hermitian Su-Schrieffer-Heeger model. We emulate this model by a 1D chain of spinless electrons evolving under unitary dynamics and subject to periodic measurements that are stochastically invoked. The non-Hermitian topology is visible in topological invariants adapted to the context of monitored circuits. For instance, the topological phase diagram of the monitored realization of the non-Hermitian Su-Schrieffer-Heeger model is obtained from the biorthogonal polarization computed from an effective Hamiltonian of the monitored system. Importantly, our monitored circuit realization allows direct access to steady-state biorthogonal expectation values of generic observables, and hence, to measure physical properties of a genuine non-Hermitian model. We expect our results to be applicable more generally to a wide range of models that host non-Hermitian topological phases.
|
|
| 5. |
|
|
| 6. |
|
|
| 7. |
- Hermanns, M., et al.
(författare)
-
FQHE-the solvable limit and beyond
- 2008
-
Ingår i: Bulletin of the American Physical Society.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- We consider the quantum Hall system in the torus geometry. In the limit where the torus becomes thin, the problem is exactly solvable and the hierarchy of quantum Hall states is manifest. Explicit wave functions for a large set of them are constructed with help of conformal field theory. This construction provides a continuation from the exactly solvable limit to the experimental regime. Numerical results on 4/11 supports this picture.
|
|
| 8. |
|
|
| 9. |
- Viefers, S., et al.
(författare)
-
Quantum Hall hierarchy wave functions from conformal field theory
- 2008
-
Ingår i: Bulletin of the American Physical Society.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- It has long been known that Laughlin's wave functions, describing the fractional quantum Hall effect at filling fractions ν=1/(2k+1), can be obtained as correlation functions in conformal field theory. We show how to generalize this approach to construct explicit trial wave functions for all states in the quantum Hall hierarchy corresponding to quasiparticle (as opposed to quasihole) condensates, including the recently observed state at ν= 4/11. At the filling fractions ν= n/(2np+1) this construction exactly reproduces Jain's composite fermion wave functions. An explicit connection is made to Wen's topological classification of FQH states.
|
|
| 10. |
- Weigand, H., et al.
(författare)
-
Accounting for service value : An ontological approach
- 2015
-
Ingår i: Proceedings - International Conference on Research Challenges in Information Science. - : IEEE conference proceedings. ; , s. 159-168, s. 159-168
-
Konferensbidrag (refereegranskat)abstract
- With the growing importance of services in the modern enterprise there is a need for innovating traditional management accounting practices. In the Service Science literature, some work has been devoted to service accounting but mainly on a conceptual level. To address this research challenge, we have built an integrated service accounting framework on top of the business ontology REA. The e3value model is a useful tool to give an overall picture of a service network, which can be combined smoothly with the more detailed REA model. The result has been evaluated on the basis of the requirements and with an example from online gaming. As far as we know, it is the first worked out service accounting framework in Service Science and allows giving often-used concepts as value-in-use a precise definition.
|
|
