Persistence of coherent quantum dynamics at strong dissipation

The quantum dynamics of a two state system coupled to a bosonic reservoir with sub-Ohmic spectral density is investigated for strong friction. Numerically exact path integral Monte Carlo methods reveal that in contrast to conventional expectations, coherent dynamics never turns into incoherent decay for a broad class of spectral distributions. Coherences associated with substantial system-reservoir entanglement exist in non-equilibrium even when strong dissipation makes the thermodynamic state of the system to behave essentially classical. This may be of relevance for current experiments with nanoscale devices and bio-molecular aggregates.Comment: 5 pages, 5 figure

Corporate financing decisions under ambiguity : pecking order and liquidity policy implications

This paper addresses the following unresolved questions fromthe perspective of ambiguity theory: Why do some firms issue equity instead of debt?Why did most firms retain their cash holdings instead of distributing themas dividends in recent times? How do firms change their financing policies during a period of severe financial constraints and ambiguity, orwhen facing the threat of an unpredictable financial crisis? We analyze how the values of the firm's equity and debt are affected by ambiguity. Wealso showthat cash holdings are retained longer if the investors' ambiguity aversion bias is sufficiently large,while cash holdings become less attractivewhen the combined impact of ambiguity and ambiguity aversion is relatively low

Dissipative spin systems in non-Ohmic environments: real-time path integral Monte Carlo-simulations

In this work, I study the dynamics of spin-1/2 systems in contact with dissipative bosonic reservoirs. Investigations are motivated by recent progress in designing and controling atomic and solid state structures of growing complexity. The interplay between the bare system and the environment is of substantial importance for understanding the dynamics of such devices. Spin systems that are embedded in bosonic reservoirs are described by the famous spin-boson model and have been studied for several decades. Recent work has shown that two-level systems in contact with sub-Ohmic reservoirs are of fundamental interest in view of both theoretical considerations and their experimental relevance. This is why I focus on the dynamics of systems that couple to a sub-Ohmic environment. Additionally, impressive experimental progress in embedding quantum dots into photonic crystals encouraged me to investigate the dynamics of two-level systems coupled to surroundings with spectral gaps