Duality in quantum mechanical wave functions is manifest through the famous measurement problem. There have been several interpretations to explain this duality, but none have seen full consensus among physicists. The Copenhagen interpretation, which is at least to some extent the most widely accepted interpretation has the 'collapse' of the wave function (or state vector reduction) during measurement, does not attribute a physical reality to the wave function. Moreover, the idea of measurement having a role in defining reality shakes the very foundation of classical physics. On the other hand, the Many worlds interpretation proposed by Everett is a very brave attempt to attribute physical significance to the wave function. Though mathematically sound and elegant, 'the splitting of the universe' in the Many Worlds Interpretation completely redefines reality as we know it. We test Everett's original thought experiment in the presence of a super observer and for sequential measurements as well. We observe that the no-clone theorem helps the Many Worlds Interpretation, yet it does not provide a consistent picture for sequential measurements, unlike the Copenhagen Interpretation.
Duality in quantum mechanical wave functions is manifest through the famous measurement problem. There have been several interpretations to explain this duality, but none have seen full consensus among physicists. The Copenhagen interpretation, which is at least to some extent the most widely accepted interpretation has the 'collapse' of the wave function (or state vector reduction) during measurement, does not attribute a physical reality to the wave function. Moreover, the idea of measurement having a role in defining reality shakes the very foundation of classical physics. On the other hand, the Many worlds interpretation proposed by Everett is a very brave attempt to attribute physical significance to the wave function. Though mathematically sound and elegant, 'the splitting of the universe' in the Many Worlds Interpretation completely redefines reality as we know it. We test Everett's original thought experiment in the presence of a super observer and for sequential measurements as well. We observe that the no-clone theorem helps the Many Worlds Interpretation, yet it does not provide a consistent picture for sequential measurements, unlike the Copenhagen Interpretation.
The measurement problem in quantum mechanics has been a cause of much puzzlement over the years. The very idea of having two different versions of reality for the same system has been a cause for much debate. Often quantum mechanics textbooks follow the ‘shut up and calculate’ paradigm. This denies the opportunity for the common student to understand the consequence of one of the most elegant and beautiful aspects of science. The state of the art textbooks give a purely algebraic, perfunctory and monotonous approach where the real consequence of the system is not fully appreciated. A good reason for this is the considerable deviation of the quantum mechanical process from the commonsensical idea of truth, reality and reason. We tend to look at the world in a materialistic, deterministic, causal and objectivistic way. We tend not to accept a world of contradictions. A quantum measurement is essentially an amalgamation of contradictions, mystery and duality. It encompasses an implicit dependence on subjectivity and contradicts with causality as we know it. We look at the world as in the present. But a quantum mechanical measurement is a prediction of the future influenced by the observer or the measurer. This offers a philosophical and pedagogical conundrum. It poses a challenge on not just how our perception of the world might change in addition to providing a big challenge on how to make it compatible with the other successful theories of physics. The most common text book interpretation of quantum mechanics has been the Copenhagen Interpretation suggests the ‘collapse of the wave function’ as a mechanism of transition between duality. But a more bizarre yet elegant theory, extending quantum formalism to the classical domain, called the Many Worlds Interpretation has been catching up very quickly; it stands for the split of the universe when we make a quantum mechanical measurement. Consequently, reality as we is redefined as a universal wave function which is a superposition of several outcomes, which is incompatible with many of the successful concepts of physics and has several problems like the correct idea about probability or basis. We adapt the idea of the universal wave function, but instead suggest a continuum interpretation of quantum mechanics where the universal wave function represents the entire singular universe and the concept of atoms or electrons as conceptually a continuous part of it rather than a distinct separate entity. Such an interpretation could be compatible with other continuum theories like the Superfluid vacuum theory or the Higgs Field.
This thesis takes a look at the many-worlds interpretation (MWI) and discusses if it can become the leading interpretation of quantum mechanics. Firstly the Copenhagen interpretation is outlined and its issues relating to the measurement problem are discussed while taking recent insights in decoherence theory into account. Establishing that wave-function collapse still yields interpretational issues, I discuss the ideas of Hugh Everett, who proposed the many-worlds interpretation, and David Wallace who is a prominent advocate of the MWI. In particular I discuss and review Wallace's arguments in favor of viewing the wave-function and the many worlds realistically. The next part shortly focuses on the testability of the many-worlds interpretation and the philosophical and theoretical issues relating to probability in the MWI. I end by concluding that the no-collapse interpretations are preferable to the Copenhagen interpretation, and I argue in favor of a realistic view towards all of the worlds. Furthermore, I conclude that standard textbooks on quantum mechanics should be updated to introduce students to the insight that wave-function collapse isn't needed in forming a complete theory of quantum mechanics.
The interpretation of quantum mechanics has been disputed ever since the advent of the theory in the 1920’s. Famous are the discussions over long time between Einstein and Bohr. Einstein refused to accept the so‐called Copenhagen interpretation, where the wave function collapses at a measurement and where the outcome of the measurement is essentially accidental (“God does not play dice”). Alternative interpretations have appeared, but the Copenhagen school has dominated the thoughts throughout the decades. One interesting interpretation was formulated in 1957 by Hugh Everett at Princeton, a student of John Wheeler, which abandons the wave‐function collapse. In this model the universe is governed entirely by the Schrödinger equation, which does not allow for any collapse. In Everett’s model after a measurement the wave function is separated into different branches that do not interact. This model was left unnoticed for long time until Bryce DeWitt took it up in 1970 and termed it “Many‐Worlds Interpretation”, a term that in some sense is misleading. Everett’s model is incomplete, and it was later supplemented by the theory of decoherence, which explains how the different branches decouple as a result of the interaction with the environment. This extended model has in recent years gained increased respect, and some believe that it is the only model made available so far that is fully consistent with quantum mechanics. This interpretation can also shed some light on the development of the universe and, in particular, on the so‐called Anthropic principle, which puts human beings at the center of the development.
For over a century, scientists have been fascinated by the strange behaviour of matter at the quantum level, where particles can exist in many states at once and affect each other instantly across distances. This paper explores this realm of quantum mechanics by focusing on wave–particle duality, superposition, entanglement and the measurement problem. It shows how these concepts defy the foundations of clas-sical physics to challenge assumptions about determinism, locality, interconnection and objectivity. The paper maintains that although quantum theory works remarkably well, we lack a clear account of what kind of reality it describes, as major interpretations such as Copenhagen, Many-Worlds and objective collapse still struggle to match quantum theory’s success with a clear picture of reality. yet as its major interpretations offer com-peting and unresolved pictures of the world. Schrödinger’s cat illustrates this tension to showcase how macroscopic systems can expose the limits of observation and the line be-tween classical and quantum worlds. The paper concludes that these quantum principles are underpinned by both technical and philosophical challenges and they force us to re-think causality and the role of the observer in explaining reality.
A novel interpretation of quantum mechanics, first proposed in brief form by Hugh Everett in 1957, forms the nucleus around which this book has developed. In his interpretation, Dr. Everett denies the existence of a separate classical realm and asserts the propriety of considering a state vector for the whole universe. Because this state vector never collapses, reality as a whole is rigorously deterministic. This reality, which is described jointly by the dynamical variables and the state vector, is not the reality customarily perceived; rather, it is a reality composed of many worlds. By virtue of the temporal development of the dynamical variables, the state vector decomposes naturally into orthogonal vectors, reflecting a continual splitting of the universe into a multitude of mutually unobservable but equally real worlds, in each of which every good measurement has yielded a definite result, and in most of which the familiar statistical quantum laws hold. The volume contains Dr. Everett's short paper from 1957, "'Relative State' Formulation of Quantum Mechanics," and a far longer exposition of his interpretation, entitled "The Theory of the Universal Wave Function," never before published. In addition, other papers by Wheeler, DeWitt, Graham, and Cooper and Van Vechten provide further discussion of the same theme. Together, they constitute virtually the entire world output of scholarly commentary on the Everett interpretation. Originally published in 1973. The Princeton Legacy Library uses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press. These editions preserve the original texts of these important books while presenting them in durable paperback and hardcover editions. The goal of the Princeton Legacy Library is to vastly increase access to the rich scholarly heritage found in the thousands of books published by Princeton University Press since its founding in 1905.
The hidden variable theories are, more cumbersome and artificial—while the Copenhagen interpretation is hopelessly incomplete because of its a priori reliance on classical physics, as well as a philosophic monstrosity with a “reality” concept for the macroscopic world and denial of the same for microcosm. In recent work on the Everett (Many-Worlds) interpretation of quantum mechanics, it has increasingly been recognized that any version of the interpretation worth defending will be one in which the basic formalism of quantum mechanics is left unchanged. Properties such as the interpretation of wave-function as describing a multiverse of branching worlds, or the ascription of probabilities to the branching events, must be emergent from the unitary quantum mechanics rather than added explicitly to the mathematics. Deutsch’s strategy was to introduce a few assumptions from decision theory into the Everett interpretation and then to show how they work with quantum theory to create a natural value measure that is the same as the expectation value.