Entanglement : the unlikely story of how scientists, mathematicians, and philosophers proved Einstein's spookiest theory

Santhosh Mathew

Chen‐Pang Yeang

Summary Proposed by Einstein, Podolsky, and Rosen (EPR) in 1935, the entangled state has played a central part in exploring the foundation of quantum mechanics. At the end of the twentieth century, however, some physicists and mathematicians set aside the epistemological debates associated with EPR and turned it from a philosophical puzzle into practical resources for information processing. This paper examines the origin of what is known as quantum information. Scientists had considered making quantum computers and employing entanglement in communications for a long time. But the real breakthrough only occurred in the 1980s when they shifted focus from general-purpose systems such as Turing machines to algorithms and protocols that solved particular problems, including quantum factorization, quantum search, superdense code, and teleportation. Key to their development was two groups of mathematical manipulations and deformations of entanglement—quantum parallelism and ‘feedback EPR’—that served as conceptual templates. The early success of quantum parallelism and feedback EPR was owed to the idealized formalism of entanglement researchers had prepared for philosophical discussions. Yet, such idealization is difficult to hold when the physical implementation of quantum information processors is at stake. A major challenge for today's quantum information scientists and engineers is thus to move from Einstein et al.'s well-defined scenarios into realistic models.

Jozef Gruska, Hiroshe Imai, Hiroshi Imai

Andrei Yu. Khrennikov

The purpose of the conference (the fourth in the series of Vaxjo conferences) was to bring together scientists (physicists, mathematicians and philosophers) who are interested in foundations of quantum physics. An emphasis was made on both theory and experiment, the underlying objective being to offer to the physical, mathematical and philosophic communities a truly interdisciplinary conference as a privileged place for a scientific interaction. Due to the actual increased role of foundations in the development of quantum information theory as well as the necessity to reconsider foundations at the beginning of the new millennium, the organizers of the conference decided that it was just the right time for taking the scientific risk of trying this.

Maria Violaris, Estelle M. Inack, Sabine Hossenfelder +3 more

Steve Bertolino

Distributed by Films Media Group, 132 West 31st St., 17th Floor, New York, NY 10001; 800-257-5126Produced by Kate Dart & BBC FilmsDirected by Kate Dart2013, DVD, color, 50 min. Proceeding from the reality that codes and encryptions are at the heart of our computing, and so at the heart of our increasingly online society, this film showcases various scientists and mathematicians who are working to understand, break, or strengthen these codes – and sometimes trying to do all three at the same time. Starting with exploitations of cracks in software systems, first on the individual then the national scale, and then moving into exploring quantum mechanics, each of the people in this documentary act as brief guides to not only what is possible in cryptography, but how ongoing experimentation (both legal and illegal) is pushing the boundaries of how codes can be hacked, and how better codes can be created. The structure of the documentary benefits from being straightforward, starting with simple codes and hacks, then progressing towards more complexity and science-based cryptography in the middle, and ending with the applications of all these methods in the criminal, then geopolitical world. Each featured interviewee gets 7-8 minutes to tell their story. Some are personal, like the journalist who works for Wired magazine and got his online life hacked and deleted, while others are mostly theoretical, like the head of a lab at MIT who can prove mathematically how to keep a code’s key secret by encoding it onto photons and comparing those photons pre- and post-transmission. Some stories are a mix of both, like the mathematician at UC-Berkeley whose dissertation was to both postulate and then to build a “basic” working quantum computer. The filmmakers have done a good job selecting interesting stories within all these types to present. While the interviewees and their stories are the stars of this film, the effects occasionally threaten to overshadow them. The effects budget must have been significant, as throughout the documentary many effects shots (most of them effective but some of them quite corny) visualize or elaborate the micro-level electric or quantum events “happening” around these computations. It makes for a slick production that high school and college students may enjoy, but except in cases where the visualizations are the most effective way to understand a concept (e.g. the encoded photons) it doesn’t add all that much to the overall film. Still, for a brief spin through the world of online cryptography, this documentary keeps its high-level concepts grounded and explained very well for a general, non-scientist audience.