This paper provides a conceptual solution to the questions of what causes discoherence and where the limits of coherence might be. Coherence is reinterpreted from the cordus perspective, as being a state when all the particules have synchronised frequencies and phases thereof, i.e. a form of complementary frequency state synchronisation (CoFS). Alternatively coherence can be perceived as a special state of assembly where the particules provide for mutual preservation of the de-energised locations of each other. Cordus anticipates three mechanisms for discoherence. First, a coherent material cannot accept internal shear velocity. Second, higher temperatures lead to decoherence because phonons (internal thermal vibrations) disturb the stability. Third, more complex assemblies of matter are harder to put into coherence, and the complicating factors are expected to be the number of components in the assembly, and the variety of species (simplicity and purity). Accordingly, the upper limit for coherence could be a simple crystal, or perhaps even a virus, with a limited number of species (different molecules or elements), at low temperature. However this is thought to be an optimistic prediction. This model predicts that coherence is already unachievable at the assembly level of the smallest metal grains, mineral crystals, and cell organelles, at ambient temperature. Thus warm macroscopic objects and living creatures cannot be put into coherence or superposition. However there is no problem with having coherent domains within a discoherent body, e.g. molecules that are internally coherent. Single particules, such as electrons, are selfcoherent under any conditions. Edition 1 > Date: Monday, 9 January 2012 > Document: Pons_Cordus_6.0_CoherenceLimits_E1.0.9.doc
This paper provides a conceptual solution to the questions of what causes discoherence and where the limits of coherence might be. Coherence is reinterpreted from the cordus perspective, as being a state when all the particules have synchronised frequencies and phases thereof, i.e. a form of complementary frequency state synchronisation (CoFS). Alternatively coherence can be perceived as a special state of assembly where the particules provide for mutual preservation of the de-energised locations of each other. Cordus anticipates three mechanisms for discoherence. First, a coherent material cannot accept internal shear velocity. Second, higher temperatures lead to decoherence because phonons (internal thermal vibrations) disturb the stability. Third, more complex assemblies of matter are harder to put into coherence, and the complicating factors are expected to be the number of components in the assembly, and the variety of species (simplicity and purity). Accordingly, the upper limit for coherence could be a simple crystal, or perhaps even a virus, with a limited number of species (different molecules or elements), at low temperature. However this is thought to be an optimistic prediction. This model predicts that coherence is already unachievable at the assembly level of the smallest metal grains, mineral crystals, and cell organelles, at ambient temperature. Thus warm macroscopic objects and living creatures cannot be put into coherence or superposition. However there is no problem with having coherent domains within a discoherent body, e.g. molecules that are internally coherent. Single particules, such as electrons, are selfcoherent under any conditions. Edition 1 > Date: Monday, 9 January 2012 > Document: Pons_Cordus_6.0_CoherenceLimits_E1.0.9.doc
The Cordus principle of complementary frequency states (CoFS) is used to develop a novel descriptive model for the mechanisms underlying superfluidity and superconductivity. In both cases Cordus explains the effects as synchronisation of forces between electrons and atoms. Several associated effects are likewise explained, including quantum vortices, heat conduction in superfluids, and the Meissner effect in superconductors. Cordus also asserts that superposition does not exist, at least not the way QM conceptualises it. In particular, that the mathematics of superposition and the wavefunction are not the reality, only mathematical approximations of deeper effects, and are unreliable qualitative descriptors of those underlying mechanisms. The concept of �coherence� is reconceptualised and the reasons why that state cannot be readily achieved are discussed. Cordus also explains why Quantum mechanics, which seems to apply at the level of individual particles, does not scale up to macroscopic bodies.
The dominant paradigm in conventional physics is that of a �particle�, which this paper suggests is a badly flawed premise. The cordus particuloid is a more coherent concept in that it offers explanations of phenomena that are otherwise puzzling, and does so with one conceptual consistent framework across a wide variety of phenomena. This paper shows how entanglement is readily explained as a natural consequence of the cordus. It also introduces the principle of complementary frequency state synchronisation (CoFS) as the deeper principle beneath the Pauli exclusion principle, and coherence. It is suggested that Bell�s Theorem is only applicable to 1D point particles, and is thus generally irrelevant. Specifically, Bell�s Theorem is not an obstacle to models of hidden variables. Furthermore, it is suggested that the principle of locality is not viable in its present form, and a principle of wider locality is proposed.
Theory and experiment have not fully resolved the apparent dichotomy , which has agonized physics for the past eighty years: on the one hand, the description of microsystems by quantum mechanics and, on the other, the description of macrosystems by classical dynamics or statistical mechanics. Derivations of the time-irreversible Liouville equation for an open quantum system, based on projecting out its environment, have narrowed the gap between the quantum and classical descriptions. Yet our `classical' intuition continues to be confronted by quantum-mechanical results like the Einstein--Podolsky--Rosen paradox that challenges the classical notion of locality, or the quantum Zeno effect which suggests that the isolation of a system is not the only way to preserve its quantum state. There are two key concepts in any discussion of such issues. The first, which is responsible for the most salient nonclassical properties, is entanglement , that is partial or complete correlation or, more generally, inseparability of the elements comprising a quantum ensemble . Even after their interaction has ceased, this inseparability, originating from their past interaction, can affect the state of one element when another element is subject to a nonunitary action, such as its measurement, tracing- out, or thermalization. The second key concept is decoherence of open quantum systems, which is the consequence of their entanglement with their environment, a `meter' or a thermal `reservoir', followed by the tracing-out of the latter. Despite new insights into entanglement and decoherence, there are still no complete, unequivocal answers to the fundamental questions of the transition from quantal to classical behaviour: how do irreversibility and classicality emerge from unitarity as systems and their environments become increasingly complex ? At what stage does system--meter entanglement give rise to a classical readout of the meter? Is there an upper limit on the size or complexity of systems displaying entanglement? Major developments have opened new vistas into controlled entanglement , which is the resource of quantum information processing. However, these developments have mainly focused on ensembles of simple two- and three-level systems that are thoroughly isolated from their environments. Treatments of coherence in quantum computing have mostly assumed that only a single or a few the elements of the quantum ensemble may simultaneously undergo an uncontrolled intervention---a quantum error. Decoherence-control protocols for more general types of errors are still incomplete. In order to resolve the outstanding issues of the quantum--classical transition, and study the control of entanglement and decoherence without the foregoing restrictions, we must venture into the domain of Quantum Complex Systems (QUACS), either consisting of a large number of inseparable elements or having many coupled degrees of freedom. Our conviction is that fundamental understanding and manipulation of entanglement within QUACS or their entanglement with the environment or a meter, call for the creation of a new conceptual framework or paradigm, that would encompass phenomena common to cold atoms in laser fields, large molecules, Josephson junctions, quantum gases and solids, with the view of employing these systems for quantum information processing and computing. Progress within this paradigm should allow us to answer the questions: does entanglement play an essential role in the evolution of large collections of complex systems? What are the size and complexity limits of systems and ensembles still controllable by an external intervention? What are the most appropriate decoherence protection schemes and control algorithms? This special issue addresses the challenge of understanding in depth and manipulating the basic quantum properties of optical, atomic, molecular and condensed-matter QUACS, and large ensembles thereof. In view of the interdisciplinary character of this issue, we find it expedient to look at the presented articles not only according to the physical objects they describe, but also from a unifying standpoint. Several unifying themes may be discerned: memory effects in dephasing and relaxation; protection of quantum information by its distribution throughout the ensemble; control of decoherence and entanglement by time-dependent interventions or measurements; manifestations of entanglement in scattering off statistical ensembles; measurment-induced dynamics. The concerted discussion of the topics outlined above should help us advance the new paradigm that addresses our abilities to diagnose and manipulate the entangled states of complex quantum objects and their robustness against decoherence. These abilities are required for quantum information (QI) applications in matter--wave interferometry in molecular, semiconducting or superconducting systems. On the fundamental level, this book may help establish the notion of dynamical information exchange between quantum systems and chart in detail the route from unitarity to classicality. Further developments within the outlined paradigm should yield novel, advantageous QI processing schemes and high-sensitivity interferometers, owing to decoherence suppression and effective control of many degrees of freedom. In the long run, these strategies may prove to be the first step towards the (hitherto unattempted) use of entanglement in nanotechnology, metrology and chemistry, with potentially remarkable novel applications.
Flashing coherently rotating carbon sticks in 24Mg+24Mg collision
The present discussion rises a number of the questions. For example, is rotational coherence of large molecules necessarily destroyed in the conventionally statistical limit of structureless non-selective continuum (for fixed total spin and parity values) under the conditions of complete intramolecular energy redistribution and vibrational dephasing in the regime of strong ro-vibrational coupling? For the slow cross-symmetry phase relaxation, quantum coherent superpositions of a large number of complex configurations with, e.g., many different total angular momenta produce image of a rotation of macroscopic object with classically fixed (single) total angular momentum. Suppose that the quantum coherent superpositions involving a very large number of different good quantum numbers play a role, in a hidden form, in a formation of macroscopic world. Then why these quantum superpositions are so stable against quick aging/decay of ordered complex structures preventing or slowing down tendencies towards uniform occupation of the available phase space as prescribed by the random matrix theory? And what kind of complex macroscopic phenomena may reveal traces of partially coherent quantum superpositions involving a huge number of quantum-mechanically different integrals of motion behind of what is referred to as conservation laws in classical physics employed for the description of the macroscopic world?
Decoherence is a relatively recent concept in the field of quantum mechanics. Although the pioneers of the field must have understood that loss of phase coherence in quantum superpositions is the reason underlying the appearance of definite outcomes in the quantum measurement problem, the latter was not treated in terms of decoherence until sixty years after the formulation of quantum mechanics as described in a report by Joos and Zeh in 1983 [1]. However, soon after, the theory was developed in further detail, and experiments to measure the actual decoherence rates in various systems commenced. Today, decoherence is the main concern for another reason, i.e., the fact that superposition states must be maintained undisturbed in the quantum communication systems and decoherence presents a strong limitation for their practical application. Decoherence appears in open quantum systems, where the basic system under consideration interacts relatively strongly with an environment. Decoherence times may be as long as seconds for small atomic systems in extreme vacua, although below what is presently measurable (i.e., less than a fraction of a femtosecond) in most liquids and solids, where coupling to the surrounding molecules or atomic arrangements is strong. The relatively slow decoherence in well-isolated particle systems has been described in several recent articles on quantum optics, while the rapid decoherence in liquids and solids has not received this kind of attention. It is the purpose of the present review to fill this gap.
Coherence refers to correlations in waves. Because matter has a wave-particle nature, it is unsurprising that coherence has deep connections with the most contemporary issues in chemistry research (e.g., energy harvesting, femtosecond spectroscopy, molecular qubits and more). But what does the word "coherence" really mean in the context of molecules and other quantum systems? We provide a review of key concepts, definitions, and methodologies, surrounding coherence phenomena in chemistry, and we describe how the terms "coherence" and "quantum coherence" refer to many different phenomena in chemistry. Moreover, we show how these notions are related to the concept of an interference pattern. Coherence phenomena are indeed complex, and ambiguous definitions may spawn confusion. By describing the many definitions and contexts for coherence in the molecular sciences, we aim to enhance understanding and communication in this broad and active area of chemistry.