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We give a general proof showing that if the evolution from one state to another is not reversible, then the projective measurements on the superposition of these two states are impossible. Applying this no-go result to the Schrödinger’s cat paradox implies that if something is claimed to be a real Schrödinger’s cat, there will be no measurable difference between it and a trivial classical mixture of ordinary cats in any physically implementable process, unless raising the dead becomes reality. Other similar macroscopic quantum superpositions cannot be observed either, due to the lack of non-commuting measurement bases. Our proof does not involve any quantum interpretation theory and hypothesis. [ABSTRACT FROM AUTHOR]

We discuss V.P. Belavkin's approach to the Schrödinger cat problem and show its close relation to ideas based on superselection and interaction with the environment developed by N.P. Landsman. The purpose of the paper is to explain these ideas in the most simple possible context, namely: discrete time and separable Hilbert spaces, in order to make them accessible to those coming from the philosophy of science and not too happy with idiosyncratic notation and terminology and sophisticated mathematical tools. Conventional elementary mathematical descriptions of quantum mechanics take "measurement" to be a primitive concept. Paradoxes arise when we choose to consider smaller or larger systems as measurement devices in their own right, by making different and apparently arbitrary choices of location of the "Heisenberg cut". Various quantum interpretations have different resolutions of the paradox. In Belavkin's approach, the classical world around us does really exist, and it evolves stochastically and dynamically in time according to probability laws following from successive applications of the Born law. It is a collapse theory. The quantum/classical distinction is determined by the arrow of time. The underlying unitary evolution of the wave-function of the universe enables the designation of a collection of beables which grows as time evolves, and which therefore can be assigned random, classical trajectories. In a slogan: the past is particles, the future is a wave. We, living in the now, are located on the cutting edge between past and future. [ABSTRACT FROM AUTHOR]

This paper states and gives three applications of a novel ‘Presentist Fragmentalist’ interpretation of quantum mechanics. In a cognate paper it was explicitly shown this kind of presentism is consistent with special relativity and that it has implications for how to understand time as it relates to the Big Bang (Merriam in Axiomathes, , 2021). In this paper we narrowly focus on three applications. These are surely the most important conundrums for any proposed interpretation of quantum mechanics: Schrodinger’s Cat, Bell non-locality, and the Born rule. It will be shown that these can be handled in a consistent and intuitive way. [ABSTRACT FROM AUTHOR]

The aim of this paper is to invalidate the hypothesis that human consciousness is necessary in the quantum measurement process. In order to achieve this target, I propose a considerable modification of the Schrödinger’s cat and the Dead-Alive Physicist thought experiments, called “PIAR”, short for “Physicist Inside the Ambiguous Room”. A specific strategy has enabled me to plan the experiment in such a way as to logically justify the inconsistency of the above hypothesis and to oblige its supporters to rely on an alternative interpretation of quantum mechanics in which a real world of phenomena exists independently of our conscious mind and where observers play no special role. Moreover, the description of the measurement apparatus will be complete, in the sense that the experiment, given that it includes also the experimenter, will begin and end exclusively within a sealed room. Hence, my analysis will provide a logical explanation of the relationship between the observer and the objects of her/his experimental observation; this and a few other implications will be discussed in the fourth section and in the conclusions. [ABSTRACT FROM AUTHOR]

Certainly, a Smarandache multispace or multisystem eS is a union of m distinct spaces or systems S1; S2,..., Sm which is an appropriate model on things T in the universe because of the limitation of humans ourselves and a thing T is complex, even overlap with other things. However, nearly all observation data on T is a multiple one eS which implies Si and Sj are entangled if Si T Sj 6=;, we have to disentangle Si from Sj, 1 < i 6= j < m for hold on the reality of thing T. Thus, disentangling a multi-space eS to self-enclosed spaces or systems S1; S2,..., Sm is interesting, also valuable in hold on the reality of things in the universe. The main purpose of this paper is to discuss the disentangling ways on a Smarandache multispace or multisystem if we assume that each self-enclosed space or system of Si; 1 < i < m is endowed with mathematical elements such as those of topological, geometrical, algebraic structures or generally, each space or system of Si has a character i different from others for integers 1 < i < m. As it happens, this problem is equivalent to Schrodinger's cat of quantum mechanics in the case of m = 2, which are extensively applied in quantum teleportation for preparation, distribution and measurement of the entangled pairs of particles and prospecting us to design a general key carrier on the Smarandachely entangling pairs in commutation. [ABSTRACT FROM AUTHOR]

Why does such a successful theory like Quantum Mechanics have so many mysteries? The history of this theory is replete with dubious interpretations and controversies, and yet a knowledge of its predictions, however, contributed to the amazing technological revolution of the last hundred years. In its very beginning Einstein pointed out that there was something missing, due to contradictions with the relativity theory. So, even though Quantum Mechanics explains all the nanoscale physical phenomena, there were many attempts to find a way to "complete" it, e.g. hidden-variable theories. In this paper, we discuss some of those enigmas, with special attention to the concepts of physical reality imposed by quantum mechanics, the role of the observer, prediction limits, a definition of collapse, and how to deal with correlated states (the basic strategy for quantum computers and quantum teleportation). That discussion is carried out within the framework of accepting that there is in fact nothing important missing, rather we are just restricted by the limitations imposed by quantum mechanics. The mysteries are thus explained by a proper interpretation of those limitations, which is achieved by introducing two interpretation rules within the Copenhagen paradigm. [ABSTRACT FROM AUTHOR]

A semiclassical phase‐space perspective of band‐ and topological‐insulator regimes of 2D Dirac materials and normal‐ and superradiant phases of atom‐field interacting models is given in terms of delocalization, entropies, and quantum correlation measures. From this point of view, the low‐energy limit of tight‐binding models describing the electronic band structure of topological 2D Dirac materials such as phosphorene and silicene with tunable band gaps share similarities with Rabi‐Dicke and Jaynes‐Cummings atom‐field interaction models, respectively. In particular, the edge state of the 2D Dirac materials in the topological insulator phase exhibits a Schrödinger's cat structure similar to the ground state of two‐level atoms in a cavity interacting with a one‐mode radiation field in the superradiant phase. Delocalization seems to be a common feature of topological insulator and superradiant phases. [ABSTRACT FROM AUTHOR]

The aim of this paper is to refute the hypothesis that the observer’s consciousness is necessary in the quantum mechanics measurement process. In order to achieve our target, we propose and investigate a variation of the Schrödinger’s cat thought experiment called “DAP”, short for “Dead-Alive Physicist”, in which a human being replaces the cat. This strategy enables us to logically disprove the consistency of the above hypothesis, and to oblige its supporters either to be trapped in solipsism or to rely on an alternative interpretation of quantum mechanics in which the conscious observer plays the sole role of acknowledging the experimental results. Our analysis hence provides support to clarify the relationship between the observer and the objects of her/his experimental observation; this and a few other implications are discussed in the fourth section and in the conclusions. [ABSTRACT FROM AUTHOR]

Recently, Frauchiger and Renner proposed a Gedankenexperiment, which was claimed to be able to prove that quantum theory cannot consistently describe the use of itself. Here we show that the conclusions of Frauchiger and Renner actually came from their incorrect description of some quantum states. With the correct description there will be no inconsistent results, no matter which quantum interpretation theory is used. Especially, the Copenhagen interpretation can satisfy all the three assumptions (C), (Q), and (S) of Frauchiger and Renner simultaneously, thus it has no problem consistently describing the use of itself. [ABSTRACT FROM AUTHOR]

The Frauchiger–Renner Paradox is an extension of paradoxes based on the "Problem of Measurement," such as Schrödinger's Cat and Wigner's Friend. All these paradoxes stem from assuming that quantum theory has only unitary (linear) physical dynamics, and the attendant ambiguity about what counts as a 'measurement'—i.e., the inability to account for the observation of determinate measurement outcomes from within the theory itself. This paper discusses a basic inconsistency arising in the FR scenario at a much earlier point than the derived contradiction: namely, the inconsistency inherent in treating an improper mixture (reduced density operator) as a proper, epistemic mixture. This is an illegitimate procedure that is nevertheless endemic if quantum theory is assumed to be always unitary. In contrast, under a non-unitary account of quantum state reduction yielding determinate outcomes, the use of a proper mixture for measurement results becomes legitimate, and this entire class of paradoxes cannot be mounted. The conclusion is that the real lesson of the FR paradox is that it is the unitary-only assumption that needs to be critically reassessed. [ABSTRACT FROM AUTHOR]

Quantum theory is extremely successful in describing the micro cosmos. The caveat is that nobody knows what quantum objects really are. Consequently, the intention of this article is not to introduce any new formalism but to develop some ideas about the ontological meaning of quantum theory. The centerpiece of quantum theory, the Schrödinger equation, requires a deterministic development of quantum systems; measurements however show an indeterministic distribution of measurement values. All previous interpretations of quantum theory are dubious. Here we will present a new understanding of one of the key features of quantum theory, namely, of superposition. Contrary to the previous understanding of the concept, we assume that superposition represents an oscillation between different states. This will lead to a completely new understanding of the universe and of quantum objects. Quantum objects are no longer considered to be elements in space, rather they are considered to be properties of space, namely, possibilities for interaction. The new understanding also leads to the conclusion that space and time are discrete. This entirely new concept will finally provide some relief for Schrödinger's cat. [ABSTRACT FROM AUTHOR]

This paper reviews and suggests a resolution of the problem of definite outcomes of measurement. This problem, also known as ‘Schrodinger’s cat’, has long posed an apparent paradox because the state resulting from a measurement appears to be a quantum superposition in which the detector is in two macroscopically distinct states (alive and dead in the case of the cat) simultaneously. Many alternative interpretations of the quantum mathematical formalism, and several alternative modifications of the theory, have been proposed to resolve this problem, but no consensus has formed supporting any one of them. Applying standard quantum theory to the measurement state, together with the analysis and results of decades of nonlocality experiments with pairs of entangled systems, this paper shows the entangled measurement state is not a paradoxical macroscopic superposition ofstates. It is instead a phase-dependent superposition ofcorrelations between statesof the subsystems. Thus Schrodinger’s cat is a non-paradoxical ‘macroscopic correlation’ in which one of the two correlated systems happens to be a detector. This insight resolves the problem of definite outcomes but it does not entirely resolve the measurement problem because the entangled state is still reversible. [ABSTRACT FROM AUTHOR]

In this article I explore the possibility of being able to hear the sound of a quantum superposition of two sounds. What would it mean and is it feasible to explore performing an experiment that would allow us to test this notion? [ABSTRACT FROM AUTHOR]

The question whether quantum mechanics is complete and the nature of the transition between quantum mechanics and classical mechanics have intrigued physicists for decades. There have been many experimental breakthroughs in creating larger and larger quantum superposition and entangled states since Erwin Schrödinger proposed his famous thought experiment of putting a cat in a superposition of both alive and dead states in 1935. Remarkably, recent developments in quantum optomechanics and electromechanics may lead to the realisation of quantum superposition of living microbes soon. Recent evidence also suggests that quantum coherence may play an important role in several biological processes. In this review, we first give a brief introduction to basic concepts in quantum mechanics and the Schrödinger’s cat thought experiment. We then review developments in creating quantum superposition and entangled states and the realisation of quantum teleportation. Non-trivial quantum effects in photosynthetic light harvesting and avian magnetoreception are also discussed. At last, we review recent proposals to realise quantum superposition, entanglement and state teleportation of micro-organisms, such as viruses and bacteria.ABSTRACT FROM PUBLISHERCopyright of Contemporary Physics is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. [ABSTRACT FROM AUTHOR]

Schrödinger's thought experiment to prepare a cat in a superposition of both alive and dead states reveals profound consequences of quantum mechanics and has attracted enormous interests. Here we propose a straightforward method to create quantum superposition states of a living microorganism by putting a small cryopreserved bacterium on top of an electromechanical oscillator. Our proposal is based on recent developments that the center-of-mass oscillation of a 15-μm-diameter aluminum membrane has been cooled to its quantum ground state (Teufel et al. in Nature 475:359, ), and entangled with a microwave field (Palomaki et al. in Science 342:710, ). A microorganism with a mass much smaller than the mass of the electromechanical membrane will not significantly affect the quality factor of the membrane and can be cooled to the quantum ground state together with the membrane. Quantum superposition and teleportation of its center-of-mass motion state can be realized with the help of superconducting microwave circuits. More importantly, the internal states of a microorganism, such as the electron spin of a glycine radical, can be entangled with its center-of-mass motion and teleported to a remote microorganism. Our proposal can be realized with state-of-the-art technologies. The proposed setup is a quantum-limited magnetic resonance force microscope. Since internal states of an organism contain information, our proposal also provides a scheme for teleporting information or memories between two remote organisms. [ABSTRACT FROM AUTHOR]

Both science and philosophy have been characterized as seeking to understand the nature of reality. They are sometimes even pitted against each other, suggesting that the success of science undermines the relevance of philosophy. But attending to the sort of understanding or explanation being sought offers a different picture: contemporary physics as practiced sometimes fails to provide a clear physical account of the world. This lies at the root of the dissatisfaction with standard quantum theory expressed by Einstein, Schrodinger, and John Bell. As an example, close consideration of Schrodinger's famous cat example suggests that physicists often havemissed his point.What a philosophical disposition can contribute is not alternative physics, but rather the sort of careful attention to argument needed to extract a physical picture from a mathematical formalism. [ABSTRACT FROM AUTHOR]

Experimental control of quantum systems has been pursued widely since the invention of quantum mechanics. Today, we can in fact experiment with individual quantum systems, deterministically preparing superpositions and entanglements. In his Nobel lecture, D. J. Wineland gives an overview of this research which has led to the Nobel prize in physics in 2012. [ABSTRACT FROM AUTHOR]

The article discusses a macroscopic system consisted of a single radioactive particle and a cat, referencing to a study that was conducted by researcher Erwin Schrödinger in 1935. It mentions how experimental control of quantum systems was pursued following the invention of quantum mechanics. It explains the extrapolation of quantum mechanics from individual quantum systems.

The geometric phase and quantum entanglement for a nonlinear field-atom system are described quantitatively in terms of different parameters. Specifically, considering a deformed Schrödinger cat interacting with a qubit and taking into account the time dependent of the system coupling. The results show that the initial state setting, atomic motion, photon number and deformation play important roles in the evolution of the system dynamics, nonlocal correlation and geometric phase. An interesting correlation between the entanglement and geometric phase is observed during the time evolution. The presented system is very useful to generate and maintain high amount of entanglement through controlling the phase variation of the system under consideration. We test this observation with experimentally accessible parameters and some new aspects are obtained. [ABSTRACT FROM AUTHOR]

This paper is a review of our recent work on three notorious problems of non-relativistic quantum mechanics: realist interpretation, quantum theory of classical properties, and the problem of quantum measurement. A considerable progress has been achieved, based on four distinct new ideas. First, objective properties are associated with states rather than with values of observables. Second, all classical properties are selected properties of certain high entropy quantum states of macroscopic systems. Third, registration of a quantum system is strongly disturbed by systems of the same type in the environment. Fourth, detectors must be distinguished from ancillas and the states of registered systems are partially dissipated and lost in the detectors. The paper has two aims: a clear explanation of all new results and a coherent and contradiction-free account of the whole quantum mechanics including all necessary changes of its current textbook version. [ABSTRACT FROM AUTHOR]

[Display omitted] • All measurement comparisons require quantity equalization. • J. C. Maxwell's quantity value is the form of all measurement results. • A quantity value explains the Mach-Zehnder interferometer experiments. • Defining a quantity requires calibration. • Calibration explains Schrödinger's Cat. In many quantum measurement experiments and thought experiments, unexplained results appear. As example, entangled particles appear to interact instantly across distances. A 2018 Measurement paper (Relative Measurement Theory, K. Krechmer, 2018) proposed that the calibration of a measuring apparatus to a reference is required in both quantum measurement models and empirical measurement results. Current quantum measurement models equalize the units but not to a reference. Current empirical measurement indications are equalized to a reference. These two measurements are different. The lack of calibration to a reference in quantum mechanics creates this difference. Including calibration explains the results of the particle spin experiments, quantum teleportation experiments, and Mach-Zehnder interferometer experiments, as well as Mermin's device, Schrödinger's Cat, and other thought experiments. [ABSTRACT FROM AUTHOR]

Difficulties and discomfort with the interpretation of quantum mechanics are due to differences in language between it and classical physics. Analogies to the special theory of relativity, which also required changes in the basic world-view and language of nonrelativistic classical mechanics, may help in absorbing the changes called for by quantum physics. There is no need to invoke extravagances such as the many-worlds interpretation or specify a central role for consciousness or neural microstructures. The simple, but basic, acceptance that what is meant by the state of a physical system is different in quantum physics from what it is in classical physics goes a long way in explaining its seeming peculiarities. [ABSTRACT FROM AUTHOR]

This paper is an enquiry into the circumstances under which entropy and subentropy methods can give an answer to the question of quantum entanglement in the composite state. Using a general quantum dynamical system, we obtain the analytical solution when the atom initially starts from its excited state and the field in different initial states. Different features of the entanglement are investigated when the field is initially assumed to be in a coherent state, an even coherent state (Schrödinger cate state), and a statistical mixture of coherent states. Our results show that the setting of the initial state and the Stark shift play important roles in the evolution of the sub-entropies and entanglement. [ABSTRACT FROM AUTHOR]

Abstract: Recent experiments appear to have revealed the possibility of the existence of quantum entanglement between spatially separated human subjects. In addition, a similar condition might exist between basins containing human neurons adhering to printed circuit boards. In both instances, preliminary data indicates what appear to be non-local correlations between brain electrical activities in the case of the human subjects and also non-local correlations between neuronal basin electrical activities, implying entanglement at the macroscopic level. If the ongoing expanded research and the analysis of same continues to support this hypothesis, it may then make it possible to simultaneously address some of the fundamental problems facing us in both physics and biology through the adoption of an interdisciplinary empirical approach based on Bell''s experimental philosophy, with the goal of unifying these two fields. [Copyright &y& Elsevier]

I present results of recent work in the field of quantum optics and relate this work to discussions about the theory of quantum mechanics and God’s divine action in the world. Experiments involving atomic decay, relevant to event uncertainty in quantum mechanics, as well as experiments aimed at elucidating the so–called Schrödinger’s–cat paradox, help clarify apparent ambiguities or paradoxes that I believe are at the heart of renewed attempts to locate God within our constructed physical theories and tend to narrow the gaps proposed as an opening for divine action. Some problems arise because of imprecise use of nonmathematical language to force quantum mechanics into an intuitive “classical” framework. [ABSTRACT FROM AUTHOR]

We consider the dynamics of the simplest Schrödinger's cat composed by a superposition of two canonical coherent states of the Schrödinger quantum harmonic oscillator. We demonstrate that the interchange of the "alive" and "dead" constituents in the whole Schrödinger's cat wave function opens the possibility to reveal one interesting, but obviously, only formal analogy with the Pauli exclusion principle. We show analytically and computationally that the symmetric cat states will occupy the ground state of the harmonic oscillator, whereas the antisymmetric cat states, vice versa, will never occupy the ground state when these states closely approach in space each other. The antisymmetric overlapping in space and time "alive" and "dead" Schrödinger cat states simply jump onto the first excited energy level of the quantum harmonic oscillator. This effect could be considered as the formal analogy of the Pauli exclusion principle applied to the antisymmetric "jumping off" Schrödinger cats. As the name suggests, the main feature of the "jumping off" Schrödinger cat consists in the transformation of the probability distribution (both in ordinary coordinate space and in the momentum space as well) in such a way that antisymmetric "alive" and "dead" cats are found to be in the first excited energy state of the quantum harmonic oscillator. We conclude that the wave and particle-like analogies in the dynamics of the symmetric and antisymmetric Schrödinger's cat states confirm at least formally the famous Pauli statements that "a symmetric solution can never develop into an antisymmetric one, and vice versa", and that "for particles with antisymmetric states it can, therefore, never happen that two particles find themselves in the same state" [ABSTRACT FROM AUTHOR]

We consider the dynamics of the simplest Schrödinger's cat composed by a superposition of two canonical coherent states of the Schrödinger quantum harmonic oscillator. We demonstrate that the interchange of the "alive" and "dead" constituents in the whole Schrödinger's cat wave function opens the possibility to reveal one interesting, but obviously, only formal analogy with the Pauli exclusion principle. We show analytically and computationally that the symmetric cat states will occupy the ground state of the harmonic oscillator, whereas the antisymmetric cat states, vice versa, will never occupy the ground state when these states closely approach in space each other. The antisymmetric overlapping in space and time "alive" and "dead" Schrödinger cat states simply jump onto the first excited energy level of the quantum harmonic oscillator. This effect could be considered as the formal analogy of the Pauli exclusion principle applied to the antisymmetric "jumping off" Schrödinger cats. As the name suggests, the main feature of the "jumping off" Schrödinger cat consists in the transformation of the probability distribution (both in ordinary coordinate space and in the momentum space as well) in such a way that antisymmetric "alive" and "dead" cats are found to be in the first excited energy state of the quantum harmonic oscillator. We conclude that the wave and particle-like analogies in the dynamics of the symmetric and antisymmetric Schrödinger's cat states confirm at least formally the famous Pauli statements that "a symmetric solution can never develop into an antisymmetric one, and vice versa", and that "for particles with antisymmetric states it can, therefore, never happen that two particles find themselves in the same state" [ABSTRACT FROM AUTHOR]

We consider how the higher-energy excited Schrödinger's cats can be transformed into the even and odd winking states, the main feature of which consists in the periodic jumping of the probability density distribution from one to other regions of space. In particular, the winking states can be formed among closely displaced ground and arbitrary-order coherent states involved into the Schrödinger's "alive" and "dead" cat dynamics. From a pedagogical standpoint it is worth mentioning that the general analytical solution for arbitrary-order winking states can be obtained practically without any calculations. We use only the method of mathematical induction and the "often forgotten" quantum-mechanical Husimi and Taniuti symmetry transformation. We show that the Husimi and Taniuti gauge invariance establishes a one to one correspondence between the harmonic oscillator eigenstates and the higher-energy coherent states of the same order in such a way that their space and time-dependent phase factors are identical for all orders of coherent states. By way of illustration, we exemplify the main logical-operation properties of winking states up to the fifth-order. [ABSTRACT FROM AUTHOR]

A Hamiltonian formalism for the Schrödinger's cat problem is outlined as well as the concept of quantum reversibility. It is noted that a characteristic of a dead animal is the absence of will. It is argued that this entity is not amenable to reversible Hamiltonian dynamics but may be represented as an infinitesimal complex component of the Hamiltonian that destroys its hermiticity and the reversibility of the Schrödinger equation. It follows that the process in which the eigenfunction representing the live state of the cat transforms to the eigenfunction of the dead state of the cat is not reversible. A discussion of Schrödinger's cat states is included. [ABSTRACT FROM AUTHOR]

The observation that distantly separated entangled particles exhibit correlations demands a new interpretation of quantum mechanics. In order to avoid a contradiction with relativity regarding the speed of light as a limiting velocity, the individual particles must be regarded as possessing intrinsic, fixed, and complementary quantum states even before an observer performs a measurement. There is no contradiction with quantum mechanics when calculated probabilities are viewed as purely statistical, applicable only to ensembles of identically prepared systems using the law of large numbers. [ABSTRACT FROM AUTHOR]