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Quantum Vacuum influence on the evolution of Pulsars

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 Added by Carlo Rizzo
 Publication date 2010
  fields Physics
and research's language is English
 Authors Arnaud Dupays




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In this letter we show that Quantum Vacuum Friction (QVF) should play an important role in neutron star evolution. Taking into account this effect we show that magnetars could be understood as a natural evolution of standard pulsars. For the Crab pulsar, of which the characteristic age is known, we present the first completely coherent time evolution for its period and braking index. For this pulsar we also give the predicted value of the current first derivative of the braking index, providing a very important test to confirm QVF.

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We introduce a framework to study the emergence of time and causal structure in quantum many-body systems. In doing so, we consider quantum states which encode spacetime dynamics, and develop information theoretic tools to extract the causal relationships between putative spacetime subsystems. Our analysis reveals a quantum generalization of the thermodynamic arrow of time and begins to explore the roles of entanglement, scrambling and quantum error correction in the emergence of spacetime. For instance, exotic causal relationships can arise due to dynamically induced quantum error correction in spacetime: there can exist a spatial region in the past which does not causally influence any small spatial regions in the future, but yet it causally influences the union of several small spatial regions in the future. We provide examples of quantum causal influence in Hamiltonian evolution, quantum error correction codes, quantum teleportation, holographic tensor networks, the final state projection model of black holes, and many other systems. We find that the quantum causal influence provides a unifying perspective on spacetime correlations in these seemingly distinct settings. In addition, we prove a variety of general structural results and discuss the relation of quantum causal influence to spacetime quantum entropies.
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We study the evolution of close binary systems composed of a normal, intermediate mass star and a neutron star considering a chemical composition typical of that present in globular clusters (Z = 0.001). We look for similarities and differences with respect to solar composition donor stars, which we have extensively studied in the past. As a definite example, we perform an application on one of the redbacks located in a globular cluster. We performed a detailed grid of models in order to find systems that represent the so-called redback binary radio pulsar systems with donor star masses between 0.6 and 2.0 solar masses and orbital periods in the range 0.2 - 0.9 days. We find that the evolution of these binary systems is rather similar to those corresponding to solar composition objects, allowing us to account for the occurrence of redbacks in globular clusters, as the main physical ingredient is the irradiation feedback. Redback systems are in the quasi-RLOF state, that is, almost filling their corresponding Roche lobe. During the irradiation cycle the system alternates between semi-detached and detached states. While detached the system appears as a binary millisecond pulsar, called a redback. Circumstellar material, as seen in redbacks, is left behind after the previous semi-detached phase. The evolution of binary radio pulsar systems considering irradiation successfully accounts for, and provides a way for, the occurrence of redback pulsars in low-metallicity environments such as globular clusters. This is the case despite possible effects of the low metal content of the donor star that could drive systems away from redback configuration.
The coupling between single-photon emitters and phonons opens many possibilities to store and transmit quantum properties. In this paper we apply the independent boson model to describe the coupling between an optically driven two-level system and a discrete phonon mode. Tailored optical driving allows not only to generate coherent phonon states, but also to generate coherent superpositions in the form of Schrodinger cat states in the phonon system. We analyze the influence of decay and dephasing of the two-level system on these phonon preparation protocols. We find that the decay transforms the coherent phonon state into a circular distribution in phase space. Although the dephasing between two exciting laser pulses leads to a reduction of the interference ability in the phonon system, the decay conserves it during the transition into the ground state. This allows to store the phonon quantum state properties in the ground state of the single-photon emitter.
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