News

New Dilution cryostat arrives! Bluefors2 is wired up and ready to go

We've just commissioned our new cryostat. It has some special features including a new active vibration isolation system, and 150 superconducting DC lines for biasing LOTS of qubits.


Pritzker NanoFabrication Facility Our brand new state of the art cleanroom has opened!

Some of the capabilities of this new facility can be found here. Our groups research was highlighted in a recent press release. See the construction of our cleanroom.


Come join us at the APS March Meeting! Baltimore, Maryland, March 14-18, 2016

Our lab will be travelling to March Meeting soon. Come find us! Here is a list of our talks and posters:


Congrats to Taekwan and Victoria! Future PhDs!

Schuster Lab undergrads are going to be PhDs next year! Taekwan, Victoria, and Sam have all been accepted to excellent schools. Andrew Oriani to join us through the IME. Congratulations!


Superbowl Party! Lots of fun at the Schusters! Oh and the Broncos won!

Dave, Heather, Ian, and Nora Joy (her first one!) hosted the annual Superbowl party at the Schuster abode. As usual, there was an expansive feast for all the members of the lab and their better halves, courtesy of Dave and Heather. The night was filled with exciting round of games and stimulating conversations. Oh and there was a football game! 'Go Broncos!' - resident Denverite, Nate Earnest.


Coupling an ensemble of electrons on superfluid helium to a superconducting circuit In press at Physical Review X

The quantized lateral motional states and the spin states of electrons trapped on the surface of superfluid helium have been proposed as basic building blocks of a scalable quantum computer. Circuit quantum electrodynamics (cQED) allows strong dipole coupling between electrons and a high-Q superconducting microwave resonator, enabling such sensitive detection and manipulation of electron degrees of freedom. Here we present the first realization of a hybrid circuit in which a large number of electrons are trapped on the surface of superfluid helium inside a coplanar waveguide resonator. The high finesse of the resonator allows us to observe large dispersive shifts that are many times the linewidth and make fast and sensitive measurements on the collective vibrational modes of the electron ensemble, as well as the superfluid helium film underneath. Furthermore, a large ensemble coupling is observed in the dispersive regime during experiment, and it shows excellent agreement with our numeric model. The coupling strength of the ensemble to the cavity is found to be 1 MHz per electron, indicating the feasibility of achieving single electron strong coupling.


Time- and Site- Resolved Dynamics in a Topological Circuit Published in Physical Review X

From studies of exotic quantum many-body phenomena to applications in spintronics and quantum information processing, topological materials are poised to revolutionize the condensed matter frontier and the landscape of modern materials science. Accordingly, there is a broad effort to realize topologically non-trivial electronic and photonic materials for fundamental science as well as practical applications. In this work, we demonstrate the first simultaneous site- and time- resolved measurements of a time reversal invariant topological band-structure, which we realize in a radio frequency (RF) photonic circuit. We control band-structure topology via local permutation of a traveling wave capacitor-inductor network, increasing robustness by going beyond the tight-binding limit. We observe a gapped density of states consistent with a modified Hofstadter spectrum at a flux per plaquette of ϕ=π/2. In-situ probes of the band-gaps reveal spatially-localized bulk-states and de-localized edge-states. Time-resolved measurements reveal dynamical separation of localized edge-excitations into spin-polarized currents. The RF circuit paradigm is naturally compatible with non-local coupling schemes, allowing us to implement a M"{o}bius strip topology inaccessible in conventional systems. This room-temperature experiment illuminates the origins of topology in band-structure, and when combined with circuit quantum electrodynamics (QED) techniques, provides a direct path to topologically-ordered quantum matter.


High-Contrast Qubit Interactions Using Multimode Cavity QED Published in Physical Review Letters

We introduce a new multimode cavity QED architecture for superconducting circuits that can be used to implement photonic memories, more efficient Purcell filters, and quantum simulations of photonic materials. We show that qubit interactions mediated by multimode cavities can have exponentially improved contrast for two qubit gates without sacrificing gate speed. Using two qubits coupled via a three-mode cavity system we spectroscopically observe multimode strong couplings up to 102 MHz and demonstrate suppressed interactions off resonance of 10 kHz when the qubits are ≈600 MHz detuned from the cavity resonance. We study Landau-Zener transitions in our multimode systems and demonstrate quasiadiabatic loading of single photons into the multimode cavity in 25 ns. We introduce an adiabatic gate protocol to realize a controlled-Z gate between the qubits in 95 ns and create a Bell state with 94.7% fidelity. This corresponds to an on/off ratio (gate contrast) of 1000.