Dr Fabio Costa

ARC DECRA

Physics
Faculty of Science
f.costa@uq.edu.au
+61 7 336 57415

Overview

Qualifications

  • Doctor of Philosophy, University of Vienna

Publications

  • Pikovski, Igor, Zych, Magdalena, Costa, Fabio and Brukner, Časlav (2017) Time dilation in quantum systems and decoherence. New Journal of Physics, 19 2: . doi:10.1088/1367-2630/aa5d92

  • Abbott, Alastair A., Giarmatzi, Christina, Costa, Fabio and Branciard, Cyril (2016) Multipartite causal correlations: polytopes and inequalities. Physical Review A, 94 3: 032131-1-032131-12. doi:10.1103/PhysRevA.94.032131

  • Ringbauer, Martin, Giarmatzi, Christina, Chaves, Rafael, Costa, Fabio, White, Andrew G. and Fedrizzi, Alessandro (2016) Experimental test of nonlocal causality. Science Advances, 2 8: . doi:10.1126/sciadv.1600162

View all Publications

Grants

View all Grants

Available Projects

  • All fundamental interactions known in nature are local: only close-by systems can interact. But where does the very notion of closeness come from? Ultimately, we only learn about spatial relations through physical systems, it should thus be possible to understand the locality of interactions without pre-assuming the existence of an absolute space.

    The aim of the project is to derive the local structure of quantum systems from properties of dynamics alone, with no reference to any underlying geometry. Formally, the task is to derive a decomposition of Hilbert space in tensor factors, with each factor representing a local subsystem, from basis-independent properties of the Hamiltonian.

    Available as Honours Project.

  • Quantum information has developed in the last decades into a broad field, offering several promising applications for future technology and deep insights into the foundations of physics. Very recently, first steps have been made in the direction of theoretically characterising and experimentally manipulating causal relations between quantum systems from an information-theoretical perspective. The motivations are two-fold: from a foundational perspective, it is expected that the notion of definite, classical causal structure would not survive in a theory where gravity, and thus space-time, are subject to quantum effects. More practically, it has been proposed that quantum causal relations can also be realised in laboratory experiments and that they can provide advantage for several tasks, such as computation and communication complexity.

    As this is a very new field, it still needs development of basic tools and exemplary protocols. To name but a few possibilities:

    · Communication: how does indefinite causal structure affect the possibility of communicating classical or quantum information?

    · Discrimination of causal structure: Given a set of events and some prior information about their causal relations, what are the optimal protocols for inferring the causal structure?

    · Teleportation of causal structure: is it possible to exploit “entangled causal relations” to effectively teleport an unknown causal structure from a set of events to another?

    · Information measures on indefinite causal structure: what are meaningful ways to quantify information encoded in systems with indefinite causal structure? Is it possible to quantify information about the causal structure itself?

    The aim of the project is to develop some of these tools, having in mind potential applications to information-theoretical tasks, quantum technologies, or foundational questions.

    Available both as Honours or PhD Project.

  • General relativity predicts the possibility of space-time geometries that contain closed time-like curves (CTCs), along which a particle could travel back in time and interact with its past self. Studies of simple bouncing billiard balls along CTCs have revealed a surprising feature: Given the initial position and velocity of the ball, there are typically multiple solutions of the equations of motion, namely many different trajectories compatible with the initial conditions [1]. This result is in striking contrast with the determinism traditionally associated with classical physics and opens the question of what type of predictions are possible in the presence of CTCs.

    The aim of this project is to develop a method to make probabilistic predictions for classical systems near CTCs, both considering specific examples—such as the billiard ball problem [1]—and developing a general formalism. The results will be compared with those derived from a quantum-mechanical modelling of the problem [2].

    The project requires a basic knowledge of the formalism of General Relativity and possibly of the path-integral formulation of quantum mechanics.

    [1] F. Echeverria, G. Klinkhammer, and K. S. Thorne, Phys. Rev. D 44, 1077 (1991).

    [2] H. D. Politzer, Phys. Rev. D 49, 3981 (1994).

View all Available Projects

Publications

Journal Article

Conference Publication

  • Zych, M., Pikovski, I., Costa, F. and Brukner, C. (2016). General relativistic effects in quantum interference of "clocks". In: 8th Symposium on Frequency Standards and Metrology 2015. 8th Symposium on Frequency Standards and Metrology 2015, Potsdam, Germany, (). 12 - 16 October 2015. doi:10.1088/1742-6596/723/1/012044

Grants (Administered at UQ)

Possible Research Projects

Note for students: The possible research projects listed on this page may not be comprehensive or up to date. Always feel free to contact the staff for more information, and also with your own research ideas.

  • All fundamental interactions known in nature are local: only close-by systems can interact. But where does the very notion of closeness come from? Ultimately, we only learn about spatial relations through physical systems, it should thus be possible to understand the locality of interactions without pre-assuming the existence of an absolute space.

    The aim of the project is to derive the local structure of quantum systems from properties of dynamics alone, with no reference to any underlying geometry. Formally, the task is to derive a decomposition of Hilbert space in tensor factors, with each factor representing a local subsystem, from basis-independent properties of the Hamiltonian.

    Available as Honours Project.

  • Quantum information has developed in the last decades into a broad field, offering several promising applications for future technology and deep insights into the foundations of physics. Very recently, first steps have been made in the direction of theoretically characterising and experimentally manipulating causal relations between quantum systems from an information-theoretical perspective. The motivations are two-fold: from a foundational perspective, it is expected that the notion of definite, classical causal structure would not survive in a theory where gravity, and thus space-time, are subject to quantum effects. More practically, it has been proposed that quantum causal relations can also be realised in laboratory experiments and that they can provide advantage for several tasks, such as computation and communication complexity.

    As this is a very new field, it still needs development of basic tools and exemplary protocols. To name but a few possibilities:

    · Communication: how does indefinite causal structure affect the possibility of communicating classical or quantum information?

    · Discrimination of causal structure: Given a set of events and some prior information about their causal relations, what are the optimal protocols for inferring the causal structure?

    · Teleportation of causal structure: is it possible to exploit “entangled causal relations” to effectively teleport an unknown causal structure from a set of events to another?

    · Information measures on indefinite causal structure: what are meaningful ways to quantify information encoded in systems with indefinite causal structure? Is it possible to quantify information about the causal structure itself?

    The aim of the project is to develop some of these tools, having in mind potential applications to information-theoretical tasks, quantum technologies, or foundational questions.

    Available both as Honours or PhD Project.

  • General relativity predicts the possibility of space-time geometries that contain closed time-like curves (CTCs), along which a particle could travel back in time and interact with its past self. Studies of simple bouncing billiard balls along CTCs have revealed a surprising feature: Given the initial position and velocity of the ball, there are typically multiple solutions of the equations of motion, namely many different trajectories compatible with the initial conditions [1]. This result is in striking contrast with the determinism traditionally associated with classical physics and opens the question of what type of predictions are possible in the presence of CTCs.

    The aim of this project is to develop a method to make probabilistic predictions for classical systems near CTCs, both considering specific examples—such as the billiard ball problem [1]—and developing a general formalism. The results will be compared with those derived from a quantum-mechanical modelling of the problem [2].

    The project requires a basic knowledge of the formalism of General Relativity and possibly of the path-integral formulation of quantum mechanics.

    [1] F. Echeverria, G. Klinkhammer, and K. S. Thorne, Phys. Rev. D 44, 1077 (1991).

    [2] H. D. Politzer, Phys. Rev. D 49, 3981 (1994).