TY  - JOUR
A1  - Müller, Matthias M.
A1  - Haakh, Harald R.
A1  - Calarco, Tommaso
A1  - Koch, Christiane P.
A1  - Henkel, Carsten
T1  - Prospects for fast Rydberg gates on an atom chip
JF  - Quantum information processing
N2  - Atom chips are a promising candidate for a scalable architecture for quantum information processing provided a universal set of gates can be implemented with high fidelity. The difficult part in achieving universality is the entangling two-qubit gate. We consider a Rydberg phase gate for two atoms trapped on a chip and employ optimal control theory to find the shortest gate that still yields a reasonable gate error. Our parameters correspond to a situation where the Rydberg blockade regime is not yet reached. We discuss the role of spontaneous emission and the effect of noise from the chip surface on the atoms in the Rydberg state.
KW  - Optimal control
KW  - Phase gate
KW  - Rydberg atoms
KW  - Cavity quantum electrodynamics
Y1  - 2011
U6  - https://doi.org/10.1007/s11128-011-0296-0
SN  - 1570-0755
VL  - 10
IS  - 6
SP  - 771
EP  - 792
PB  - Springer
CY  - New York
ER  - 
TY  - JOUR
A1  - Schlosser, Rainer
A1  - Chenavaz, Régis Y.
A1  - Dimitrov, Stanko
T1  - Circular economy
BT  - joint dynamic pricing and recycling investments
JF  - International journal of production economics
N2  - In a circular economy, the use of recycled resources in production is a key performance indicator for management. Yet, academic studies are still unable to inform managers on appropriate recycling and pricing policies. We develop an optimal control model integrating a firm's recycling rate, which can use both virgin and recycled resources in the production process. Our model accounts for recycling influence both at the supply- and demandsides. The positive effect of a firm's use of recycled resources diminishes over time but may increase through investments. Using general formulations for demand and cost, we analytically examine joint dynamic pricing and recycling investment policies in order to determine their optimal interplay over time. We provide numerical experiments to assess the existence of a steady-state and to calculate sensitivity analyses with respect to various model parameters. The analysis shows how to dynamically adapt jointly optimized controls to reach sustainability in the production process. Our results pave the way to sounder sustainable practices for firms operating within a circular economy.
KW  - Dynamic pricing
KW  - Recycling investments
KW  - Optimal control
KW  - General demand function
KW  - Circular economy
Y1  - 2021
U6  - https://doi.org/10.1016/j.ijpe.2021.108117
SN  - 0925-5273
SN  - 1873-7579
VL  - 236
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Kalkuhl, Matthias
A1  - Steckel, Jan Christoph
A1  - Edenhofer, Ottmar
T1  - All or nothing
BT  - climate policy when assets can become stranded
JF  - Journal of environmental economics and management
N2  - This paper develops a new perspective on stranded assets in climate policy using a partial equilibrium model of the energy sector. Political-economy related aspects are considered in the government's objective function. Lobbying power of firms or fiscal considerations by the government lead to time inconsistency: The government will deviate from a previously announced carbon tax which creates stranded assets. Under rational expectations, we show that a time-consistent policy outcome exists with either a zero carbon tax or a prohibitive carbon tax that leads to zero fossil investments - an "all-or-nothing" policy. Although stranded assets are crucial to such a bipolar outcome, they disappear again under time-consistent policy. Which of the two outcomes (all or nothing) prevails depends on the lobbying power of owners of fixed factors (land and fossil resources) but not on fiscal revenue considerations or on the lobbying power of renewable or fossil energy firms.
KW  - Climate policy
KW  - Optimal control
KW  - Political economy
KW  - Public finance
KW  - Credible policy
KW  - Time inconsistency
Y1  - 2020
U6  - https://doi.org/10.1016/j.jeem.2019.01.012
SN  - 0095-0696
SN  - 1096-0449
VL  - 100
PB  - Elsevier
CY  - San Diego
ER  -