In quantum information science, the phase of a wave function plays an important role in encoding information. Although most experiments this field rely on dynamic effects to manipulate information, alternative approach is use geometric phase, which has been argued have potential fault tolerance. We demonstrated controlled accumulation Berry's superconducting qubit; we manipulated qubit geometrically by means microwave radiation and observed accumulated interference experiment. found...

We present an ideal realization of the Tavis-Cummings model in absence atom number and coupling fluctuations by embedding a discrete fully controllable superconducting qubits at fixed positions into transmission line resonator. Measuring vacuum Rabi mode splitting with one, two, three strongly coupled to cavity field, we explore both bright dark dressed collective multiqubit states observe $\sqrt{N}$ scaling dipole strength. Our experiments demonstrate novel approach states, such as $W$...

Quantum coherence in solid-state systems has been demonstrated superconducting circuits and semiconductor quantum dots. This paved the way to investigate for information processing with potential benefit of scalability compared other based on atoms, ions photons. Coherent coupling microwave photons, circuit electrodynamics (QED), opened up new research directions enabled long distance qubits. Here we demonstrate how electromagnetic field a resonator can be coupled double dot. The charge...

The experimental investigation of quantum devices incorporating mechanical resonators has opened up new frontiers in the study mechanics at a macroscopic level$^{1,2}$. Superconducting microwave circuits have proven to be powerful platform for realisation such devices, both cavity optomechanics$^{3,4}$, and circuit electro-dynamics (QED)$^{5,6}$. While most experiments date involved localised nanomechanical resonators, it recently been shown that propagating surface acoustic waves (SAWs) can...

We present measurements of coherence and successive decay dynamics higher energy levels a superconducting transmon qubit. By applying consecutive π pulses for each sequential transition frequency, we excite the qubit from ground state up to its fourth excited level characterize state. find proceed mainly sequentially, with relaxation times in excess 20 μs all transitions. also provide direct measurement charge dispersion these by analyzing beating patterns Ramsey fringes. The results...

We demonstrate the time-resolved driving of two-photon blue sideband transitions between superconducting qubits and a transmission line resonator. As an example using these for two-qubit operation, we implement pulse sequence that first entangles one qubit with resonator subsequently distributes entanglement two qubits. show generation 75% fidelity Bell states by this method. The full density matrix system is extracted joint measurement quantum state tomography shows close agreement...

High quality on-chip microwave resonators have recently found prominent new applications in quantum optics and information processing experiments with superconducting electronic circuits, a field now known as circuit electrodynamics (QED). They are also used single photon detectors parametric amplifiers. Here we analyze the physical properties of coplanar waveguide their relation to materials for use QED. We designed fabricated fundamental frequencies from 2 9 GHz factors ranging few...

We present spectroscopic measurements of the Autler-Townes doublet and sidebands Mollow triplet in a driven superconducting qubit. The ground to first excited state transition qubit is strongly pumped while resulting dressed spectrum probed with weak tone. corresponding transitions are detected using dispersive readout coupled off resonantly microwave transmission line resonator. observed frequencies spectral lines good agreement Jaynes-Cummings model taking into account higher states level...

Quantum state tomography is an important tool in quantum information science for complete characterization of multiqubit states and their correlations. Here we report a method to perform joint simultaneous readout two superconducting qubits dispersively coupled the same mode microwave transmission line resonator. The nonlinear dependence resonator on qubit dependent cavity frequency allows us extract full two-qubit correlations without need single-shot individual qubits. We employ standard...

We present the realization of a cavity quantum electrodynamics setup in which photons strongly different lifetimes are engineered harmonic modes same cavity. achieve this superconducting transmission line resonator with qubits coupled to modes. One mode is detection for qubit state readout, while second long lifetime used photon storage and coherent operations. demonstrate sideband based measurement coherence, generation n Fock states scaling Rabi frequency square root using scheme that may...

We present systematic measurements of the quality factors surface acoustic wave (SAW) resonators on ST-X quartz in gigahertz range at a temperature $10\phantom{\rule{0.16em}{0ex}}\mathrm{mK}$. demonstrate an internal factor ${Q}_{\mathrm{i}}$ approaching $0.5$ million $0.5\phantom{\rule{0.16em}{0ex}}\text{GHz}$ and show that ${Q}_{\mathrm{i}}\ensuremath{\ge}4.0\ifmmode\times\else\texttimes\fi{}{10}^{4}$ is achievable up to $4.4\phantom{\rule{0.16em}{0ex}}\text{GHz}$. evidence for polynomial...

Quantum computation requires the precise control of evolution a quantum system, typically through application discrete logic gates on set qubits. Here, we use cross-resonance interaction to implement gate between two superconducting transmon qubits with direct static dispersive coupling. We demonstrate practical calibration procedure for optimization gate, combining continuous and repeated-gate Hamiltonian tomography step-wise reduction dominant two-qubit coherent errors mapping microwave...

Abstract Using quantum systems with more than two levels, or qudits, can scale the computational space of processors efficiently using qubits, which may offer an easier physical implementation for larger Hilbert spaces. However, individual qudits exhibit noise, and algorithms designed qubits require to be recompiled qudit execution. In this work, we implemented a two-qubit emulator 4-level superconducting transmon variational algorithm applications analyzed its noise model. The major source...

We demonstrate charge pumping in semiconducting carbon nanotubes by a traveling potential wave. From the observation of nanotube insulating state we deduce that transport occurs packets being carried along By tuning side gate, either electron or hole can be realized. Prospects for realization based single-electron pumps are discussed.

Quantum theory predicts that empty space is not truly empty. Even in the absence of any particles or radiation, pure vacuum, virtual are constantly created and annihilated. In an electromagnetic field, presence photons manifests itself as a small renormalization energy quantum system, known Lamb shift. We present experimental observation shift solid-state system. The strong dispersive coupling superconducting electronic circuit acting bit (qubit) to vacuum field transmission-line resonator...

We report heating rate measurements in a microfabricated gold-on-sapphire surface electrode ion trap with trapping height of approximately 240 μm. Using the Doppler recooling method, we characterize rates over an extended region trap. The noise spectral density falls range spectra reported traps at room temperature. find that during first months operation, increase by one order magnitude. is largest ion-loading trap, providing strong hint contamination plays major role for excessive rates....

The quantum properties of electromagnetic, mechanical or other harmonic oscillators can be revealed by investigating their strong coherent coupling to a single two level system in an approach known as cavity electrodynamics (QED). At temperatures much lower than the characteristic energy spacing observation vacuum Rabi oscillations mode splittings with one few quanta asserts nature oscillator. Here, we study how classical response QED emerges from when its thermal occupation---or effective...

The quantum state of a superconducting qubit nonresonantly coupled to transmission line resonator can be determined by measuring the quadrature amplitudes an electromagnetic field transmitted through resonator. We present experiments in which we analyze detail dynamics as function measurement frequency for both weak continuous and pulsed measurements. find excellent agreement between our data calculations based on set Bloch-type differential equations cavity derived from dispersive...

We present microwave frequency measurements of the dynamic admittance a quantum dot tunnel coupled to two-dimensional electron gas. The are made via high-quality 6.75 GHz on-chip resonator capacitively dot. is found shift both down and up close conductance resonance corresponding change sign reactance system from capacitive inductive. observations consistent with scattering matrix model. depends on detuning magnitude rate lead respect frequency. Inductive response observed resonance, when...

Surface acoustic wave (SAW) devices based on thin films of ZnO are a well established technology. However, SAW bulk crystals not practical at room temperature due to the significant damping caused by finite electrical conductivity crystal. Here, operating low temperatures, we demonstrate effective (0001) surface crystals, including delay line wavelengths λ = 4 and 6 μm one-port resonator wavelength 1.6 μm. We find that velocity is dependent, reaching v ≃ 2.68 km/s 10 mK. Our reaches maximum...

Coupling between a crystal of di(phenyl)-(2,4,6-trinitrophenyl)iminoazanium radicals and superconducting microwave resonator is investigated in circuit quantum electrodynamics (circuit QED) architecture. The exhibits paramagnetic behavior above 4 K, with antiferromagnetic correlations appearing below this temperature, we demonstrate strong coupling at base temperature. magnetic resonance acquires field angle dependence as the cooled down, indicating anisotropy exchange interactions. These...

We report high qubit coherence as well low cross-talk and single-qubit gate errors in a superconducting circuit architecture that promises to be tileable two-dimensional (2D) lattices of qubits. The integrates an inductively shunted cavity enclosure into design featuring nongalvanic out-of-plane control wiring qubits resonators fabricated on opposing sides substrate. proof-of-principle device features four uncoupled transmon exhibits average energy relaxation times T1 = 149(38) μs, pure...

Decoherence in superconducting quantum circuits, caused by loss mechanisms like material imperfections and two-level system (TLS) defects, remains a major obstacle to improving the performance of devices. In this work, we present atomic-level characterization cross-sections Josephson junction spiral resonator assess quality critical interfaces. Employing scanning transmission electron microscopy (STEM) combined with energy-dispersive X-ray spectroscopy (EDS) electron-energy (EELS), identify...