Dr Eran Ginossar
Lecturer
Email: e.ginossar@surrey.ac.uk
Phone: Work: 01483 68 2714
Room no: 20 ATI 02
Office hours
Please e-mail me to schedule a meeting or regarding applications for PhD.
Further information
Biography
Eran Ginossar grew up in Israel, where he obtained his BSc in Physics from Tel-Aviv University. During his graduate
studies at the Weizmann Institute of Science in Rehovot he worked on extending the theory of optical spin
orientation of direct gap semiconductors to include the fluctuations of the light and of the spins. After receiving
his PhD in 2008 he moved to Yale University to study the physics of superconducting circuits, a field that is
rapidly progressing in creating viable devices for quantum information processing. Additional topics of interest
include interaction effects in mesoscopic systems, quantum optics and quantum simulations. Eran has joined the
Department of Physics and the Advanced Technology Institute at the University of Surrey in 2011. He is a member of
the APS and an EPSRC fellow.
Research Interests
Circuit Quantum Electrodynamics: Measurement theory and control of Qubits and Resonators. These projects are geared towards developing the building blocks and protocols for quantum information processing with solid state devices. My research in this field is strongly motivated by experiments which routinely raise research questions in quantum optics and coherent control. The methodology involves taking a non-equilibrium open system approach to modeling and employing large scale computer simulations.
Semiconductor quantum optics: The theory of optical spin orientation of direct gap semiconductors can include the fluctuations of the light and of the spins. Our analysis treats the effects of optical photonic correlations, present in down converted light, on the collective fluctuations of the spins excited by the light. This shows a possibility to control the temporal fluctuations of the collective electronic spin in actual semiconductor devices, demonstrating that quantum optical effects can appear in the optical absorption of squeezed light by a semiconductor.
Mesoscopic physics: Electronic interferometers in the quantum Hall state, persistent currents in normal metal rings, random lasers.
Publications
Highlights
- .
(2010) 'Response of the strongly driven Jaynes-Cummings oscillator.'. American Physical Society Phys Rev Lett, United States: 105 (10) Article number 100505 Full text is available at: http://epubs.surrey.ac.uk/38233/
Abstract
We analyze the Jaynes-Cummings model of quantum optics, in the strong-dispersive regime. In the bad-cavity limit and on time scales short compared to the atomic coherence time, the dynamics are those of a nonlinear oscillator. A steady-state nonperturbative semiclassical analysis exhibits a finite region of bistability delimited by a pair of critical points, unlike the usual dispersive bistability from a Kerr nonlinearity. This analysis explains our quantum trajectory simulations that show qualitative agreement with recent experiments from the field of circuit quantum electrodynamics.
- .
(2010) 'Protocol for high-fidelity readout in the photon-blockade regime of circuit QED'. AMER PHYSICAL SOC PHYSICAL REVIEW A, 82 (2) Article number ARTN 022335 Full text is available at: http://epubs.surrey.ac.uk/38232/
- . (2009) 'Persistent currents in normal metal rings.'. Science, United States: 326 (5950), pp. 272-275.
- .
(2008) 'Behavior of electronic interferometers in the nonlinear regime.'. American Physical Society Phys Rev Lett, United States: 100 (19) Article number 196806 Full text is available at: http://epubs.surrey.ac.uk/37672/
Abstract
We investigate theoretically the behavior of the current oscillations in an electronic Mach-Zehnder interferometer (MZI) as a function of its source bias. Recently, the MZI visibility data showed an unexplained lobe pattern with a peculiar phase rigidity. Moreover, the effect did not depend on the MZI path length difference. We argue that these effects may be a new many-body manifestation of particle-wave duality in quantum mechanics. When biasing the interferometer sources so much that multiple electrons are on each arm at any instant in time, quantum shot noise (a particle phenomena) must affect the interference pattern of the electrons that create it. A solution to the interaction Hamiltonian presented here shows that the interference visibility has a lobe pattern with applied bias that has a period proportional to the average path length and independent of the path length difference, together with a phase rigidity.
Journal articles
- .
(2013) 'Suppression of the radiative decay of atomic coherence in squeezed
vacuum'. Quantum Physics, Full text is available at: http://epubs.surrey.ac.uk/749750/
Abstract
Quantum fluctuations of the electromagnetic vacuum are responsible for physical effects such as the Casimir force and the radiative decay of atoms, and set fundamental limits on the sensitivity of measurements. Entanglement between photons can produce correlations that result in a reduction of these fluctuations below the vacuum level allowing measurements that surpass the standard quantum limit in sensitivity. Here we demonstrate that the radiative decay rate of an atom that is coupled to quadrature squeezed electromagnetic vacuum can be reduced below its natural linewidth. We observe a two-fold reduction of the transverse radiative decay rate of a superconducting artificial atom coupled to continuum squeezed vacuum generated by a Josephson parametric amplifier, allowing the transverse coherence time T_2 to exceed the vacuum decay limit of 2T_1. We demonstrate that the measured radiative decay dynamics can be used to tomographically reconstruct the Wigner distribution of the the itinerant squeezed state. Our results are the first confirmation of a canonical prediction of quantum optics and open the door to new studies of the quantum light-matter interaction.
- .
(2012) 'Observation of quantum state collapse and revival due to the
single-photon Kerr effect'. Full text is available at: http://epubs.surrey.ac.uk/749139/
Abstract
Photons are ideal carriers for quantum information as they can have a long coherence time and can be transmitted over long distances. These properties are a consequence of their weak interactions within a nearly linear medium. To create and manipulate nonclassical states of light, however, one requires a strong, nonlinear interaction at the single photon level. One approach to generate suitable interactions is to couple photons to atoms, as in the strong coupling regime of cavity QED systems. In these systems, however, one only indirectly controls the quantum state of the light by manipulating the atoms. A direct photon-photon interaction occurs in so-called Kerr media, which typically induce only weak nonlinearity at the cost of significant loss. So far, it has not been possible to reach the single-photon Kerr regime, where the interaction strength between individual photons exceeds the loss rate. Here, using a 3D circuit QED architecture, we engineer an artificial Kerr medium which enters this regime and allows the observation of new quantum effects. We realize a Gedankenexperiment proposed by Yurke and Stoler, in which the collapse and revival of a coherent state can be observed. This time evolution is a consequence of the quantization of the light field in the cavity and the nonlinear interaction between individual photons. During this evolution non-classical superpositions of coherent states, i.e. multi-component Schroedinger cat states, are formed. We visualize this evolution by measuring the Husimi Q-function and confirm the non-classical properties of these transient states by Wigner tomography. The single-photon Kerr effect could be employed in QND measurement of photons, single photon generation, autonomous quantum feedback schemes and quantum logic operations.
- .
(2012) 'Quantum State Sensitivity of an Autoresonant Superconducting Circuit'. Physics Review B, Full text is available at: http://epubs.surrey.ac.uk/729045/
Abstract
When a frequency chirped excitation is applied to a classical high-Q nonlinear oscillator, its motion becomes dynamically synchronized to the drive and large oscillation amplitude is observed, provided the drive strength exceeds the critical threshold for autoresonance. We demonstrate that when such an oscillator is strongly coupled to a quantized superconducting qubit, both the effective nonlinearity and the threshold become a non-trivial function of the qubit-oscillator detuning. Moreover, the autoresonant threshold is sensitive to the quantum state of the qubit and may be used to realize a high fidelity, latching readout whose speed is not limited by the oscillator Q.
- .
(2010) 'High-cooperativity coupling of electron-spin ensembles to superconducting cavities.'. American Physical Society Phys Rev Lett, United States: 105 (14) Article number 140501 Full text is available at: http://epubs.surrey.ac.uk/37910/
Abstract
Electron spins in solids are promising candidates for quantum memories for superconducting qubits because they can have long coherence times, large collective couplings, and many qubits could be encoded into spin waves of a single ensemble. We demonstrate the coupling of electron-spin ensembles to a superconducting transmission-line cavity at strengths greatly exceeding the cavity decay rates and comparable to the spin linewidths. We also perform broadband spectroscopy of ruby (Al₂O₃:Cr(3+)) at millikelvin temperatures and low powers, using an on-chip feedline. In addition, we observe hyperfine structure in diamond P1 centers.
- .
(2010) 'Quantum non-demolition detection of single microwave photons in a circuit'. NATURE PUBLISHING GROUP NATURE PHYSICS, 6 (9), pp. 663-667.doi: 10.1038/NPHYS1710Full text is available at: http://epubs.surrey.ac.uk/732760/
- .
(2010) 'Response of the strongly driven Jaynes-Cummings oscillator.'. American Physical Society Phys Rev Lett, United States: 105 (10) Article number 100505 Full text is available at: http://epubs.surrey.ac.uk/38233/
Abstract
We analyze the Jaynes-Cummings model of quantum optics, in the strong-dispersive regime. In the bad-cavity limit and on time scales short compared to the atomic coherence time, the dynamics are those of a nonlinear oscillator. A steady-state nonperturbative semiclassical analysis exhibits a finite region of bistability delimited by a pair of critical points, unlike the usual dispersive bistability from a Kerr nonlinearity. This analysis explains our quantum trajectory simulations that show qualitative agreement with recent experiments from the field of circuit quantum electrodynamics.
- .
(2010) 'Protocol for high-fidelity readout in the photon-blockade regime of circuit QED'. AMER PHYSICAL SOC PHYSICAL REVIEW A, 82 (2) Article number ARTN 022335 Full text is available at: http://epubs.surrey.ac.uk/38232/
- .
(2010) 'Mesoscopic persistent currents in a strong magnetic field'. AMER PHYSICAL SOC PHYSICAL REVIEW B, 81 (15) Article number ARTN 155448 Full text is available at: http://epubs.surrey.ac.uk/37945/
- . (2009) 'Persistent currents in normal metal rings.'. Science, United States: 326 (5950), pp. 272-275.
- .
(2009) 'Proposal for generating and detecting multi-qubit GHZ states in circuit QED'. IOP PUBLISHING LTD NEW JOURNAL OF PHYSICS, 11 Article number ARTN 073040 Full text is available at: http://epubs.surrey.ac.uk/38235/
- .
(2008) 'Coherent optical control of correlation waves of spins in semiconductors'. AMER PHYSICAL SOC PHYSICAL REVIEW B, 78 (20) Article number ARTN 205204 Full text is available at: http://epubs.surrey.ac.uk/37878/
- .
(2008) 'Behavior of electronic interferometers in the nonlinear regime.'. American Physical Society Phys Rev Lett, United States: 100 (19) Article number 196806 Full text is available at: http://epubs.surrey.ac.uk/37672/
Abstract
We investigate theoretically the behavior of the current oscillations in an electronic Mach-Zehnder interferometer (MZI) as a function of its source bias. Recently, the MZI visibility data showed an unexplained lobe pattern with a peculiar phase rigidity. Moreover, the effect did not depend on the MZI path length difference. We argue that these effects may be a new many-body manifestation of particle-wave duality in quantum mechanics. When biasing the interferometer sources so much that multiple electrons are on each arm at any instant in time, quantum shot noise (a particle phenomena) must affect the interference pattern of the electrons that create it. A solution to the interaction Hamiltonian presented here shows that the interference visibility has a lobe pattern with applied bias that has a period proportional to the average path length and independent of the path length difference, together with a phase rigidity.
- .
(2008) 'Optical manipulation of collective spin correlations in semiconductors with a squeezed vacuum of polarized photons'. AMER PHYSICAL SOC PHYSICAL REVIEW B, 77 (3) Article number ARTN 035307 Full text is available at: http://epubs.surrey.ac.uk/37935/
- .
(2007) 'Atom in a coherently controlled squeezed vacuum'. AMER PHYSICAL SOC PHYSICAL REVIEW A, 76 (1) Article number ARTN 013821 Full text is available at: http://epubs.surrey.ac.uk/37618/
- .
(2005) 'Semiconductor Microstructure in a Squeezed Vacuum: Electron-Hole Plasma
Luminescence'. American Physical Society Physical Review B (Condensed Matter and Materials Physics), 72 (7) Article number 075333 Full text is available at: http://epubs.surrey.ac.uk/13488/
Abstract
We consider a semiconductor quantum-well placed in a wave guide microcavity and interacting with the broadband squeezed vacuum radiation, which fills one mode of the wave guide with a large average occupation. The wave guide modifies the optical density of states so that the quantum well interacts mostly with the squeezed vacuum. The vacuum is squeezed around the externally controlled central frequency $\om_0$, which is tuned above the electron-hole gap $E_g$, and induces fluctuations in the interband polarization of the quantum-well. The power spectrum of scattered light exhibits a peak around $\om_0$, which is moreover non-Lorentzian and is a result of both the squeezing and the particle-hole continuum. The squeezing spectrum is qualitatively different from the atomic case. We discuss the possibility to observe the above phenomena in the presence of additional non-radiative (e-e, phonon) dephasing.
Book chapters
- . (2012) 'Nonlinear oscillators and high fidelity qubit state measurement in circuit quantum electrodynamics'. in (ed.) Fluctuating Nonlinear Oscillators. From nanomechanics to quantum superconducting circuits Oxford University Press Article number 8
Internet publications
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(2001) Universal Features of Interacting Chaotic Quantum Dots. Application to
Statistics of Coulomb Blockade Peak Spacings. Full text is available at: http://epubs.surrey.ac.uk/729046/
Abstract
We present a complete classification of the electron-electron interaction in chaotic quantum dots based on expansion in inverse powers of $1/M$, the number of the electron states in the Thouless window, $M \simeq k_F R$. This classification is quite universal and extends and enlarges the universal non interacting RMT statistical ensembles. We show that existing Coulomb blockade peak spacing data for $B=0$ and $B\ne 0$ is described quite accurately by the interacting GSE and by its extension to $B\ne 0$. The bimodal structure existing in the interacting GUE case is completely washed out by the combined effect of the spin orbit, pairing and higher order residual interactions.
Teaching
Level 1 Essential Mathematics
There are Ph.D. positions available see
http://www.surrey.ac.uk/ati/tac/activity/projects/
and please e-mail enquires to e.ginossar@surrey.ac.uk
