TY - JOUR A1 - Seibold, Götz A1 - Lorenzana, José T1 - Magnetic fluctuations of stripes in the high temperature cuprate superconductors Y1 - 2005 ER - TY - CHAP A1 - Hokamp, Sascha A1 - Seibold, Götz ED - Kaminski, Bogumil ED - Koloch, Grzegorz T1 - How Much Rationality Tolerates the Shadow Economy? – An Agent-Based Econophysics Approach T2 - Advances in social simulation : proceedings of the 9th Conference of the European Social Simulation Association N2 - We calculate the size of the shadow economy within a multi-agent econophysics model previously developed for the study of tax evasion. In particular, we analyze deviating behavior depending on the fraction of rational agents which aim to pursue their self interest. Two audit mechanisms are considered within our model, that are, (i) a constant compliance period which is enforced after black market activities of an agent have been detected and (ii) a backauditing method which determines the compliance period according to the particpation rate in the shadow economy within a previously preassigned time interval. We calibrate our simulation with respect to experimental evidence of tax compliance in France and Germany and give estimates for the percentage of selfish agents in these countries. This implies different policy recommendations that may work to fight the shadow economy, tax evasion, and the like. KW - shadow economy KW - econophysics KW - multi-agent model Y1 - 2014 UR - http://link.springer.com/chapter/10.1007/978-3-642-39829-2_11 SN - 978-3-642-39828-5 U6 - https://doi.org/10.1007/978-3-642-39829-2_11 SP - 128 PB - Springer CY - Berlin [u.a.] ER - TY - GEN A1 - Bucheli, Daniel A1 - Grilli, Marco A1 - Peronaci, F. A1 - Seibold, Götz A1 - Caprara, Sergio T1 - Phase diagrams of voltage-gated oxide interfaces with strong Rashba coupling T2 - Physical Review B N2 - We propose a model for the two-dimensional electron gas formed at the interface of oxide heterostructures that includes a Rashba spin-orbit coupling proportional to an electric field oriented perpendicularly to the interface. Taking into account the electron density dependence of this electric field confining the electron gas at the interface, we report the occurrence of a phase separation instability (signaled by a negative compressibility) for realistic values of the spin-orbit coupling and of the electronic band-structure parameters at zero temperature. We extend the analysis to finite temperatures and in the presence of an in-plane magnetic field, thereby obtaining two phase diagrams that exhibit a phase separation dome. By varying the gating potential, the phase separation dome may shrink and vanish at zero temperature into a quantum critical point where the charge fluctuates dynamically. Similarly, the phase separation may be spoiled by a planar magnetic field even at zero temperature leading to a line of quantum critical points. Y1 - 2014 UR - https://journals.aps.org/prb/abstract/10.1103/PhysRevB.89.195448 U6 - https://doi.org/10.1103/PhysRevB.89.195448 SN - 2469-9969 VL - 89 ER - TY - JOUR A1 - Seibold, Götz A1 - Letz, M. A1 - Sigmund, Ernst A1 - Hizhnyakov, Vladimir T1 - Mean-Field Theories of Spin-Cluster States in copper oxide planes Y1 - 1994 ER - TY - GEN A1 - Seibold, Götz A1 - Bucheli, Daniel A1 - Caprara, Sergio A1 - Grilli, Marco T1 - Phase separation and long-wavelength charge instabilities in spin-orbit coupled systems T2 - EPL Europhysics Letters N2 - We investigate a two-dimensional electron model with Rashba spin-orbit interaction where the coupling constant $g=g(n)$ depends on the electronic density. It is shown that this dependence may drive the system unstable towards a long-wavelength charge density wave (CDW) where the associated second-order instability occurs in close vicinity to global phase separation. For very low electron densities the CDW instability is nesting-induced and the modulation follows the Fermi momentum kF. At higher density the instability criterion becomes independent of kF and the system may become unstable in a broad momentum range. Finally, upon filling the upper spin-orbit split band, finite momentum instabilities disappear in favor of phase separation alone. We discuss our results with regard to the inhomogeneous phases observed at the LaAlO3/SrTiO3 or LaTiO3/SrTiO3 interfaces. Y1 - 2015 UR - http://iopscience.iop.org/article/10.1209/0295-5075/109/17006;jsessionid=34AAE2057398BD7AE51C0C4719FC29DD.c2.iopscience.cld.iop.org U6 - https://doi.org/10.1209/0295-5075/109/17006 SN - 1286-4854 VL - 109 IS - 1 SP - 17006 ER - TY - JOUR A1 - Eremin, M. A1 - Varlamov, Sergej A1 - Eremenin, I. A1 - Seibold, Götz T1 - Influence of incommensurability on SDW and CDW amplitudes in underdoped cuprates Y1 - 2000 ER - TY - JOUR A1 - Seibold, Götz A1 - Sigmund, Ernst A1 - Hizhnyakov, Vladimir T1 - Spin-Polaron Formation and Phase Separation Y1 - 1996 ER - TY - GEN A1 - Oelsen, E. von A1 - Seibold, Götz A1 - Bünemann, Jörg T1 - Time-Dependent Gutzwiller Theory for Multiband Hubbard Models T2 - Physical Review Letters Y1 - 2011 SN - 1079-7114 VL - 107 IS - 7 SP - 076402-01 EP - 076402-04 ER - TY - GEN A1 - Berger, Wolfram A1 - Hokamp, Sascha A1 - Seibold, Götz T1 - Dynamic behavioral changes in an agent-based econophysics tax compliance model. Bomb-crater versus target effects and efficient audit strategies T2 - Journal of Public Finance and Public Choice N2 - We investigate an inhomogeneous Ising model in the context of tax evasion dynamics where different types of agents are parametrised via local temperatures and magnetic fields. Our work focuses on the dynamic behavioural change of agents after an audit which either corresponds to a temporal reduction or enhancement of compliance and is also known under the terms 'bomb crater' and 'target effect', respectively. We analyse this effect for different types of agents: endogenously non-compliant types, agents that have the tendency to copy (non-)compliant behaviour from their social environment, ethical agents with strong endogenous morale attitudes and random types that show large uctuations between compliant and non-compliant behaviour. Each type in uences the overall tax evasion differently, and interestingly, our model predicts that increasing the audit probability can have the counterintuitive effect of increasing tax evasion under certain circumstances. We analyse audit strategies that can suppress this effect and thus contribute to the burgeoning literature on the actual impact of tax audits. Y1 - 2021 U6 - https://doi.org/10.1332/251569120X15840237292628 SN - 2515-6926 VL - 36 IS - 1 SP - 3 EP - 24 ER - TY - JOUR A1 - Seibold, Götz A1 - Sigmund, Ernst A1 - Hizhnyakov, Vladimir T1 - Unrestricted slave-boson mean-field approximation for the two-dimensional Hubbard model JF - Physical review Y1 - 1998 SN - 0556-2805 VL - 57 IS - 12 SP - 6937 EP - 6942 ER -