Progress in Artificial Economics

Artificial economics aims to provide a generative approach to understanding problems in economics and social sciences. It is based on the consistent use of agent-based models and computational techniques. It encompasses a rich variety of techniques that generalize numerical analysis, mathematical programming, and micro-simulations. The peer-reviewed contributions in this volume address applications of artificial economics to markets and trading, auctions, networks, management, industry sectors, macroeconomics, and demographics and culture

The Equity Premium Puzzle: An Application of an Agent-Based Evolutionary Model

We describe an agent-based model of a financial market with a stock and a bond. Agents compete in repeated rounds, decide whether to acquire costly information and can pick one of 16 strategies to allocate their investments, under evolutionary pressure driven by the comparison of the realized short-term revenues from trading. We show that, while in- formed traders survive in some cases, the equilibrium shares are strongly biased in favor of strategies that make little use of information and sys- tematically overestimate the riskiness of the stock. As a consequence, the majority of the population ends up in buying fewer stocks than would be otherwise expected or deemed rational. This evolutionary dynamics offers a novel way to explain the equity pre- mium puzzle first described by Mehra and Prescott (The equity pre- mium: A puzzle. Journal of Monetary Economics 1985), according to which it’s hard to find reasons for the widespread lack of investment in risky assets. Evolution based on a straightforward comparison of rev- enues is a simple and cognitively appealing avenue to reach a population of traders using (over-)cautious strategies to curb the risk of long-term “financial extinction”. Simulations run in NetLogo also demonstrate that very little information may be used in noisy markets or when the cost of information is substantial

The macro and asset pricing implications of rising Italian uncertainty: Evidence from a novel news-based macroeconomic policy uncertainty index

We develop a new monthly and daily index of economic policy uncertainty for Italy based on articles from the Sole 24 Ore (a popular Italian business daily newspaper). VAR investigations document that an unexpected rise in the Sole 24 Ore news-based EPU index (EPU24) has mild effects on the real economic activity. Cross-sectional asset pricing tests then show that both monthly and daily EPU24 shocks command a positive risk premium. A standard event study finally indicates the presence of statistically significant positive cumulative abnormal returns (CARs) in the energy sector following different categories of policy-related events. Negative and significant CARs in the financial sector are instead found to be generated by international-related events and political elections

Atom-photon, atom-atom and photon-photon entanglement preparation via fractional adiabatic passage

We propose a relatively robust scheme to generate maximally entangled states of (i) an atom and a cavity photon, (ii) two atoms in their ground states, and (iii) two photons in two spatially separate high-Q cavities. It is based on the interaction via fractional adiabatic passage of a three-level atom traveling through a cavity mode and a laser beam. The presence of optical phases is emphasized.Comment: 6 pages, 7 figures. We have changed the title, the abstract and the text. The references have been updated. (Accepted by Phys. Rev. A

INFLUENCE OF DEEP CRYOGENIC TREATMENT ON THE PROPERTIES OF CONVENTIONAL AND PM HIGH SPEED STEELS

The influence of Deep Cryogenic Treatment (DCT) on the properties of four wrought and PM high speed steels was investigated. Hardness and (apparent) fracture toughness Ka were measured to highlight the possible influence of DCT carried out before and after tempering. Dry sliding wear tests were carried using a block on disc configuration. The properties of the two wrought steels, HS6-5-2 (AISI M2) and HS6-5-2-5 (AISI M35), highlight a well defined influence of DCT. HS6-5-2 shows a remarkable improvement in abrasive wear resistance without any hardness increase. The most promising result is obtained by carrying out DCT before tempering. The opposite occurs by HS6-5-2-5, containing about 4.8%Co, whose wear resistance decreases in any treatment condition including DCT. PM steels show a less significant change in properties, since these are mainly controlled by the high amount of evenly distributed primary carbides which are not influenced by DCT. A slight increase in wear resistance was observed just for HS6-5-3. A general worsening was observed for HS6-5-3-8, namely HS6-5-3 plus 8%Co. In the light of results here presented cobalt seems to play a negative effect with respect to the low temperature conditioning of martensite

Anticancer Effects and Mechanisms of CFI-400945 and Radiation in Breast Cancer

Breast cancer is a leading cause of death in women and development of new treatments is essential. Polo-like Kinase 4 (PLK4) controls centriole duplication and its inhibition by CFI-400945 induces genomic instability and aneuploidy. Radiation therapy (RT) also induces aneuploidy leading to cell death, although development of radioresistance is common. We hypothesized that CFI-400945 and RT act synergistically in breast cancer. Colony formation assays identified synergistic anticancer effects of CFI-400945 and RT, with combinatorial effects also observed for RT with either siRNA inhibition of PLK4 or with the PLK4 inhibitor Centrinone B. This suggests that the antiproliferative effect of these combinations are, at least partly, mediated through PLK4. Immunocytochemistry for Centrin showed significant overamplification of centrioles in combination compared to single agent treatment, suggesting a possible combined mechanism of action. These results support further translational studies of CFI-400945 and RT as a combination treatment to improve breast cancer outcomes

Decoherence in Ion Trap Quantum Computers

The {\it intrinsic} decoherence from vibrational coupling of the ions in the Cirac-Zoller quantum computer [Phys. Rev. Lett. {\bf 74}, 4091 (1995)] is considered. Starting from a state in which the vibrational modes are at a temperature $T$, and each ion is in a superposition of an excited and a ground state, an adiabatic approximation is used to find the inclusive probability $P(t)$ for the ions to evolve as they would without the vibrations, and for the vibrational modes to evolve into any final state. An analytic form is found for $P(t)$ at $T=0$, and the decoherence time is found for all $T$. The decoherence is found to be quite small, even for 1000 ions.Comment: 11 pages, no figures, uses revte

Codes for the Quantum Erasure Channel

The quantum erasure channel (QEC) is considered. Codes for the QEC have to correct for erasures, i. e., arbitrary errors at known positions. We show that four qubits are necessary and sufficient to encode one qubit and correct one erasure, in contrast to five qubits for unknown positions. Moreover, a family of quantum codes for the QEC, the quantum BCH codes, that can be efficiently decoded is introduced.Comment: 6 pages, RevTeX, no figures, submitted to Physical Review A, code extended to encode 2 qubits, references adde

Decoherence and Dissipation in Quantum Two-State Systems

The Brownian dynamics of the density operator for a quantum system interacting with a classical heat bath is described using a stochastic, non-linear Liouville equation obtained from a variational principle. The environment's degrees of freedom are simulated by classical harmonic oscillators, while the dynamical variables of the quantum system are two non-hermitian "square root operators" defined by a Gauss-like decomposition of the density operator. The rate of the noise-induced transitions is expressed as a function of the environmental spectral density, and is discussed for the case of the white noise and blackbody radiation. The result is compared with the rate determined by a quantum environment, calculated by partial tracing in the whole Hilbert space. The time-dependence of the von Neumann entropy and of the dissipated energy is obtained numerically for a system of two quantum states. These are the ground and first excited state of the center of mass vibrations for an ion confined in a harmonic trap.Comment: 17 pages, LaTex, 3 postscript figures; replaced to correct typo in Eq. (5

Sviluppo di un acciaio per lavorazione a caldo rinforzato tramite alligazione meccanica

I compositi a matrice metallica combinano elevata durezza e buona tenacità offrendo la possibilità di modularele loro proprietà attraverso la scelta più opportuna del tipo, frazione e dimensioni del rinforzo. La produzione dicompositi a matrice metallica basati su acciai per lavorazioni a caldo è stata poco sviluppata in letteratura. Inquesto lavoro è stata investigata la possibilità di produrre un acciaio per lavorazioni a caldo AISI H13 rinforzatocon particelle ceramiche di diversa natura quali carburi (TiC), nitruri (TiN) e boruri (TiB2). Questi compostirisultano particolarmente promettenti per applicazioni ad alta temperatura data la loro elevata stabilità termica.Le polveri composite sono state prodotte tramite macinazione meccanica, ottenendo un affinamento dellamicrostruttura e una fine distribuzione delle particelle di rinforzo. Le polveri composite sono state sinterizzatetramite la tecnica Spark Plasma, in modo da preservare la fine microstruttura prodotta durante macinazionee limitare l’interazione tra matrice e particelle rinforzanti. Il composito con il 20%vol di TiB2 mostra la migliordensificazione raggiungendo quasi densità teorica. L’analisi diffrattometrica ai raggi-x di questo materialeevidenzia però la formazione di composti secondari, quali Fe2B e TiC, indicando una parziale decomposizione delTiB2. Tra i materiali sinterizzati, il composito il TiC mostra il maggior incremento di durezza