Karoline Wiesner

Intrinsic quantum computation

We introduce ways to measure information storage in quantum systems, using a recently introduced computation-theoretic model that accounts for measurement effects. The first, the quantum excess entropy, quantifies the shared information between a quantum processs past and its future. The second, the quantum transient information, determines the difficulty with which an observer comes to know the internal state of a quantum process through measurements. We contrast these with von Neumann entropy and quantum entropy rate and provide a closed-form expression for the latter for the class of deterministic quantum processes.

Simplicity and complexity

Is anything ever simple? When confronted with a complicated system, scientists typically strive to identify underlying simplicity, which we articulate as natural laws and fundamental principles. This simplicity is what makes nature appear so organized. Atomic physics, for example, approached a solid theoretical foundation when Niels Bohr uncovered the organization of electronic energy levels, which only later were redescribed as quantum wavefunctions. Charles Darwins revolutionary idea about the origin of species emerged by mapping how species are organized and discovering why they came to be that way. And James Watson and Francis Cricks interpretation of DNA diffraction spectra was a discovery of the structural organization of genetic information – it was neither about the molecules disorder (thermodynamic entropy) nor about the statistical randomness of its base-pair sequences.

Computation in sofic quantum dynamical systems

We analyze how measured quantum dynamical systems store and process information, introducing sofic quantum dynamical systems. Using recently introduced information-theoretic measures for quantum processes, we quantify their information storage and processing in terms of entropy rate and excess entropy, giving closed-form expressions where possible. To illustrate the impact of measurement on information storage in quantum processes, we analyze two spin-1 sofic quantum systems that differ only in how they are measured.

Women in the Physical Sciences in Sweden: Do We Have True Gender Equality in a “Gender‐Neutral” Country?

Sweden, together with the other Nordic countries, seems at first glance to offer an environment where women and men enjoy equal treatment at all levels of society. Governments proclaim policies invoking gender‐neutral regulations and legal frameworks. Government‐supported parental leave programs provide paid leave for both parents, the child‐care system is well developed, women are represented at high levels in the government, and educational levels are high. Clearly, awareness of gender issues and openness in the classroom and workplace must be very high. Why, then, is the career pipeline for women in physics leaking so badly? Why are there so few women in high‐level management positions in industry? How can salaries for women on all levels, not least within the public sector, be consistently lower than for their male counterparts? What factors are important and how can we influence the situation so that women receive their fair share of power and recognition for their achievements? We discuss some of th...

Computation in Sofic Quantum Dynamical Systems

We analyze how measured quantum dynamical systems store and process information, introducing sofic quantum dynamical systems. Using recently introduced information-theoretic measures for quantum processes, we quantify their information storage and processing in terms of entropy rate and excess entropy, giving closed-form expressions where possible. To illustrate the impact of measurement on information storage in quantum processes, we analyze two spin-1 sofic quantum systems that differ only in how they are measured.