Sarah Shandera
Pennsylvania State University, PA·Physics
No observer can see the whole universe. Anyone sees only a finite region of space, over a finite time, at finite resolution.
- Fields
Physics
Astronomy & Astrophysics
- Topics
open quantum systems
quantum information
cosmology
- Grants
- 1 known grant, through Jul 2028
What they work on
- Study how quantum reference frames, the different ways observers divide a system into local subsystems, shape the ensemble of open-system dynamics, and how robust its features are when the frame changes.
- Extend open-system descriptions to local structure that is uneven and changing, set by quantum correlations, and relate the resulting behavior to quantum phases of mixed states.
- Formulate an "open effective theory" for observers built from ensembles of open quantum systems, using solvable spin models and numerical quantum-circuit models analyzed by information spreading and complexity.
More about the research
The physics such an observer can access is therefore the physics of an "open" system: a small piece of a larger whole whose hidden parts still affect what is seen. Describing physics rigorously from this limited viewpoint bears on deep questions about the origin of structure in the early universe, dark energy, and the quantum behavior of gravity and horizons. The project uses the mathematics of quantum information science to build tools for such observers.
Why it matters
This is basic theoretical physics. It aims to clarify whether viewing observers as open quantum systems can make progress on long-standing puzzles about the quantum nature of spacetime, horizons and cosmological observations. It could eventually inform how cosmologists interpret what limited observers can learn about the early universe and dark energy.
Known grants
From NIH and NSF research grants. Labs often have other funding we can't see.
Closest labs
Daniel Boyanovsky
University of Pittsburgh, PA·Physics
Calculate how axion dark matter candidates were produced, decayed, and thermalized in the early universe, using non-equilibrium effective field theory, a simplified particle-physics description for changing conditions, to predict dark matter abundance.
Yizhi You
Northeastern University, MA·Physics·Early-career
Construct microscopic models and hybrid fracton field theories to describe the collective behavior of fractons, particle-like excitations with restricted mobility, and the phases and phase transitions they form.
Soubhik Kumar
Tufts University, MA·Physics
Use effective field theory to classify the non-Gaussian signatures, unusual statistical patterns, left by heavy beyond-Standard-Model particles produced during inflation, and build templates for searches in cosmic microwave background (CMB) surveys.
The school
Pennsylvania State University: 60 labs on PI Pages, $1.3B a year on research, 743 research doctorates a year.
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