GABRIELSE RESEARCH GROUP

Professor Gerald Gabrielse
Harvard Physics Department

Lepton Magnetic Moments -- one apparatus, many results (below)

• Most accurate measurement of the electron magnetic moment
       (AIP Physics story of the year, etc.)
• Most accurate determination of the fine structure constant
• Most stringent test of quantum electrodynamics theory
• Limit on electron substructure
• Most stringent test of CPT invariance with leptons

ATRAP Antihydrogen Studies

• All slow antihydrogen experiments use our accumulation methods
• Nested Penning Trap (proposed, first demonstration with protons and electrons,
  first filling with positrons and electrons)
• First positron cooling of antiprotons (first method for making antihydrogen)
• Our first observation of slow antihydrogen atoms
(followed immediately by an improved method)
      Slow antihydrogen observations are the AIP Physics Story of the Year
• Antihydrogen velocity and an interpretation
• Laser-controlled antihydrogen production (second method to make antihydrogen)
• Antiproton confinement within a Penning-Ioffe trap
• First antihydrogen production within a Penning-Ioffe trap

Proton and Antiproton Magnetic Moments*^,**

• Goal 1: Nondestructive observations of the spin flips of a single trapped proton
• Goal 2: Measurement of a proton spin resonance using quantum jump spectroscopy
• Goal 3: Determine the magnetic moment of the proton from measured spin and cyclotron frequencies
• Goal 4: Load antiprotons into the trap and duplicate goals 1 to 3 with a single trapped antiproton
• Goal 5: Compare the antiproton and proton magnetic moments a million or more times more accurately

Why Does Sideband Mass Spectroscopy Work?

• recent PRL
• longer report

Investigation of a One-Electron Qubit

• Goal 1: To observe one electron suspended within a planar trap chip
• Goal 2: To demonstrate a one-electron qubit for the first time
• Goal 3: To couple one-electron qubits
• Goal 4: To investigate a coupled array of one-electron qubits

ACME Search for the Electric Dipole Moment of an Electron

• Use ThO molecule
• Goal is a significantly improved electron EDM measurement or limit on a 5 year time scale

Comparing Q/M of the Antiproton and Proton to 9 parts in 10¹¹

• Most stringent test of CPT invariance with a baryon system
• Nearly a million times more precise than previous CPT tests with baryons
• Series of three measurements with increasing accuracy

Methods to Slow, Trap, Electron-Cool, and Accumulate Cold Antiprotons

• Developed by the Gabrielse group and TRAP collaborators
• Used to get cold antiprotons for Q/M measurements
• Makes possible all cold antihydrogen experiments

Brown-Gabrielse Invariance Theorem:

Makes possible many of the most precise measurements in particle, atomic, and nuclear physics

• Makes possible the most accurate measurements of magnetic moments
• Makes possible the most accurate ion mass spectroscopy
• Makes possible the most accurate nuclear mass spectrometry

• derivation
• review of its use
• foundation for accurate nuclear mass measurements

Useful New Designs for Penning Traps

• Orthogonalized hyperbolic Penning traps (overview, design, damping)
• Cylindrical Penning traps (overview, design, demonstration with one electron)
• Open-access cylindrical traps (overview, design)
• Planar Penning traps (overview)

Superconducting Solenoid that Shields Magnetic Field Fluctuations

• Cancels by a factor of 250 or more any change in the external magnet field
• A flux change in the solenoid produces a current, that produces a field, that cancels the field change at the center of the system
• No active electronics
• Made it possible to do antiproton Q/M measurements not far from cycling LEAR and PS magnets
• Allows MRI imaging machines to be located nearer to elevators, etc.
• Used for stable ICR mass spectrometry (e.g. to analyze pharmaceuticals)

• design
• patent
• demonstration

Theory of One Particle in a Penning Trap

• The often-cited basic review of the properties of a charged particle in a Penning trap