Member Profile

Christoph Lange

Postdoctoral Research assistant, Department of Social and Cultural Anthropology, University of Cologne

Contributing Editor, Platypus: The CASTAC Blog

Research Interests

About Christoph

After studying Social Anthropology and Middle East Studies at the University of Leipzig from 2004–2011, he was a research assistant at the Research Lab "Transformations of Life" of the a.r.t.e.s. Graduate School for the Humanities Cologne from 2014 - 2018. Since 2018 he is working at the Department of Social and Cultural Anthropology at the University of Cologne. In 2020, Christoph successfully finished his doctoral thesis on "Decolonizing the Arabian Horse - The Breeding, Circulation and Certification of the Straight Egyptian Arabian in the 21st Century". Currently, he is developing a postdoctoral project on Liminal Infrastructures and Mediterranean Crises from a Critical Zone's perspective.

Contact

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Publications

Chapters

Paraxial Light Beams with Angular Momentum

A. Bekshaev, Marat Samuilovich Soskin, M. Vasnetsov | Nova Science Publishers (2008) | ISBN: 1604561149

Chapter: Interspecies Performance, Christoph Lange (pgs. 143-166)

Fundamental and applied concepts concerning the ability of light beams to carry a certain mechanical angular momentum (AM) with respect to the propagation axis are reviewed and discussed in this book. In paraxial beams, the total beam AM can be represented as a sum of the spin (SAM) and orbital (OAM) angular momentums. SAM is an attribute of beams with elliptic (circular) polarisation and is related to the spin of photons. OAM is conditioned by the macroscopic transverse energy circulation and does not depend on the beam polarisation state. In turn, the OAM can be divided in two components which reflect different forms of this energy circulation. Important class of beams with OAM, are vortex beams with helical geometric structure. They constitute a full set of azimuthal harmonics characterised by integer index l each possessing AM l per photon. Arbitrary paraxial beam can be represented as a superposition of helical beams with different l. Models of helical beams and methods of their practical generation are discussed. Transverse energy flows in light beams can be described on the basis of a mechanical model assimilating them to fluid bodies; remarkably, in a helical beam the transverse flow distribution exactly corresponds to the laws of the vortex behaviour in other fields of physics (fluid dynamics, electricity). Experiments on transmission of the beam AM to other bodies (optical elements and to suspended microparticles) are discussed. Research prospects and ways of practical utilisation of optical beams with AM are discussed.

Paraxial Light Beams with Angular Momentum

A. Bekshaev, Marat Samuilovich Soskin, M. Vasnetsov | Nova Science Publishers (2008) | ISBN: 1604561149

Chapter: The making and remaking of the Arabian horse – from the Arab Bedouin horse to the modern Straight Egyptian 1, Christoph Lange (pgs. 234-250)

Fundamental and applied concepts concerning the ability of light beams to carry a certain mechanical angular momentum (AM) with respect to the propagation axis are reviewed and discussed in this book. In paraxial beams, the total beam AM can be represented as a sum of the spin (SAM) and orbital (OAM) angular momentums. SAM is an attribute of beams with elliptic (circular) polarisation and is related to the spin of photons. OAM is conditioned by the macroscopic transverse energy circulation and does not depend on the beam polarisation state. In turn, the OAM can be divided in two components which reflect different forms of this energy circulation. Important class of beams with OAM, are vortex beams with helical geometric structure. They constitute a full set of azimuthal harmonics characterised by integer index l each possessing AM l per photon. Arbitrary paraxial beam can be represented as a superposition of helical beams with different l. Models of helical beams and methods of their practical generation are discussed. Transverse energy flows in light beams can be described on the basis of a mechanical model assimilating them to fluid bodies; remarkably, in a helical beam the transverse flow distribution exactly corresponds to the laws of the vortex behaviour in other fields of physics (fluid dynamics, electricity). Experiments on transmission of the beam AM to other bodies (optical elements and to suspended microparticles) are discussed. Research prospects and ways of practical utilisation of optical beams with AM are discussed.

Contributions to Platypus: The CASTAC Blog

View all of Christoph's posts on Platypus: The CASTAC Blog.

Data Swarms Revisited – New Modes of Being

Editor’s Note: The new Platypus Thematic Series entitled “Data Swarms Revisited” will feature posts form computer science, philosophy and anthropology and connect to the Thematic Series Anthropos Tomorrow: Transhumanism and Anthropology inaugurated by Jon Bialecki and Ian Lowrie on Platypus in 2017. The posts will deal with overarching questions of the so-called “human condition” in times of accelerated computation, digitalization and technological infrastructures. Herein, the figuration of the Data Swarm serves as a playful and slightly ironic approximation to the threats and promises embedded in these on-going controversies.

Origins: Searching for New Modes of Humanism(s)[note id=”1″ type=”mark”]

At the end of September 2019, it was already the fourth time that both the Research Lab of the a.r.t.e.s. Graduate School for the Humanities Cologne and the Collaborative Research Center 806 “Our Way to Europe” had invited an interdisciplinary group of international graduate students and postdoctoral researchers to meet at the Cologne Summer School of Interdisciplinary Anthropology (CSIA). For an entire week, the participants delved into the many controversies about the so-called “human condition” and what it actually means to “be human” in the 21st century.[note id=”2″ type=”mark”]

After three years of discussing the latest material and practice turns along the Phenomenality of Material Things, in 2019, the CSIA relaunched its inquiries in new modes of being and humanism(s) under the theme of Beyond Humanism: Cyborgs – Animals – Data Swarms. With an apparent elective affinity to Donna Haraway (Haraway 2016b), we picked up where the last CSIA left by taking a closer look at what trans– and posthumanist agendas actually imply and how they relate to classic understandings of the human condition. Our goal was not simply dismissing these new modes of humanism(s) as mere social phenomena in an age of accelerated technological and cultural transformations but to take them seriously in order to better understand the shifts in contemporary concepts and controversies about being human. Through historically tracing back modes of humanism and their counterparts, as well as excavating their ontological and epistemological conditions, we identified three relational contestations of what it no longer means and three figurations of what it nowadays means to be human. The contestations are: (1) the distribution of human subjectivity and cognition, (2) the disintegration of human individuality, and (3) the dissolution of humanity as a unique ontological category.

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