Daniel Carney

"We have to remember that what we observe is not nature itself, but nature exposed to our method of questioning." -Heisenberg

Contact

Email: carney@lbl.gov

Twitter: @four_form

Office: LBL 50B-5226

Research

I am a theoretical physicist, originally trained in string theory-ish physics and now working near the theory-experiment intersection. I am a staff scientist at Berkeley National Lab (in terms of tenure, roughly equivalent to an assistant professor).

I use ideas from quantum information science to learn about fundamental physics. Most of my work is centered around the theory of measurement and how it applies to particle physics and gravity. This ranges from proposing new experiments (some of which are now real!) to more formal theoretical work.

Ultimately, I strongly suspect that quantum limits to measurement will play a central role in the formulation of a consistent quantum model of general relativity. In the meantime, many of these ideas have applications beyond fundamental physics, particularly to problems in quantum metrology and computing.

You can see my full list of papers: google scholar or inspire.

• Dark matter detection:
  
  
  • Theory: Gravitational direct detection of dark matter [PRD]
  • Experiment: Search for composite dark matter with optically levitated sensors [PRL]
  • Overview paper: Mechanical quantum sensing in the search for dark matter [QST]
  • Snowmass 2021: Mechanical sensors as particle detectors
  • Talk: U. Minnesota high-energy seminar
  • Popular press: Nature (PDF), Gizmodo, New Scientist (paywall), NIST Tech Beat
    
    
• Experimental tests of quantum properties of the gravitational field
  
  
  • Using an atom interferometer to infer gravitational entanglement generation [PRX Quantum] [Errata]
  • Newton, entanglement, and the graviton
  • Tabletop experiments for quantum gravity: a user's manual [CQG]
  • Snowmass 2021: Laboratory experiments in quantum gravity
  • Talk: Latin American Physics Webinar
  • Press: Jess Riedel's blog post, NIST press release
    
    
• Quantum information content of soft gravitons and photons
  
  
  • Infrared quantum information [PRL]
  • On the need for soft dressing [JHEP]
  • Talk: Perimeter Institute quantum info seminar

With Cindy Regal (JILA), Dave Moore (Yale), and Gordan Krnjaic (Fermilab), I organized a workshop at Maryland's Joint Quantum Institute: "Quantum Optomechanical Architectures for Dark Matter Detection". Thanks to the APS and Moore Foundation, JQI, and JILA for supporting this!

Workshop #2 on optomechanics and dark matter: online and open to all, April 9, 2021.

History

2017-2020: Postdoc, joint between

• Joint Quantum Institute at University of Maryland/NIST (supervisor: Jacob Taylor)
• Theory group at Fermilab

2014-2017: Postdoc, University of British Columbia (supervisors: Philip Stamp, Bill Unruh)

2007-2014: PhD Physics, Theory Group @ University of Texas, Austin

• Dissertation: "Toward a Theory of Observation" (Artist's interpretation)
• Supervisors: Willy Fischler, Sonia Paban

2003-2007: BS Physics, BA Math, University of Cincinnati

2005: Foreign exchange student, NUPACE program @ Nagoya University, Japan

Teaching

Spring 2024: Phys 250, Quantum Theory of Measurement.

• Syllabus

• Running course notes, last updated March 4.

• Homeworks are just the problem sets in the notes, assigned via bCourse.

I have a strong interest in teaching using methods supported by modern education research. In particular, I have been heavily involved with a number of inquiry-based learning projects (notably the UTeach program). Some examples from the ancient past where I had regular teaching duties:

• In the 2012-13 academic year, I supervised, with Sonia Paban, an undergraduate thesis in physics and astronomy. The topic was on excited quantum states for inflationary perturbations. Here is the final draft (used here with permission).

• Here is the project of one of my former undergraduate UTeach students (now a public high school physics teacher in Texas), who measured the local value of the Hubble parameter (slides) using Iain Smail's excellent tutorial.