Resonant macroscopic quantum tunneling in SQUID systems

Silvestrini, P.; Ruggiero, B.; Ovchinnikov, Yu. N.

doi:10.1103/physrevb.54.1246

Cited by 21 publications

(20 citation statements)

References 18 publications

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“…A related problem has been investigated in a series of theoretical works by Ovchinnikov and co-workers [51][52][53][54][55][56] by applying semiclassical techniques. In Ref.…”

Section: B Prior Theoretical Approachesmentioning

confidence: 99%

“…More analytical oriented works in the context of dissipative multilevel bistable systems have been performed by several groups [48][49][50][51][52][53][54][55][56]. The starting point in Refs.…”

Section: B Prior Theoretical Approachesmentioning

confidence: 99%

“…Finally, the theory is adapted to SQUIDs in Ref. [56] to explain the experimental findings of Ref. [30].…”

Section: B Prior Theoretical Approachesmentioning

confidence: 99%

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Strong Coupling Theory for Tunneling and Vibrational Relaxation in Driven Bistable Systems

2001

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A study of the dynamics of a tunneling particle in a driven bistable potential which is moderatelyto-strongly coupled to a bath is presented. Upon restricting the system dynamics to the Hilbert space spanned by the M lowest energy eigenstates of the bare static potential, a set of coupled non-Markovian master equations for the diagonal elements of the reduced density matrix, within the discrete variale representation, is derived. The resulting dynamics is in good agreement with predictions of ab-initio real-time path integral simulations. Numerous results, analytical as well as numerical, for the quantum relaxation rate and for the asymptotic populations are presented. Our method is particularly convenient to investigate the case of shallow, time-dependent potential barriers and moderate-to-strong damping, where both a semi-classical and a Redfield-type approach are inappropriate.PACS: 82.20.Pm

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“…A related problem has been investigated in a series of theoretical works by Ovchinnikov and co-workers [51][52][53][54][55][56] by applying semiclassical techniques. In Ref.…”

Section: B Prior Theoretical Approachesmentioning

confidence: 99%

Section: B Prior Theoretical Approachesmentioning

confidence: 99%

See 1 more Smart Citation

Strong Coupling Theory for Tunneling and Vibrational Relaxation in Driven Bistable Systems

2001

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“…One reason of the difference is the short decoherence time of our qubit since our qubit couples strongly with the environment due to the larger size. A rough estimation 29,30 gives intrawell relaxation rate ⌫ 1 ϳ͑1 nS͒ −1 , interwell relaxation rate between ͉0R͘ and ͉0L͘ ⌫ inter ϳ͑1 S͒ −1 , and dephasing rate ⌫ 2 ϳ͑0.5 nS͒ −1 , which are appropriate for our qubit. Another reason of the difference is that we used an order of magnitude higher MW frequency.…”

mentioning

confidence: 99%

Population inversion induced by Landau–Zener transition in a strongly driven rf superconducting quantum interference device

Sun

Wen

Wang

et al. 2009

Applied Physics Letters

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Microwave resonances between discrete macroscopically distinct quantum states with single photon and multiphoton absorption are observed in a strongly driven radio frequency superconducting quantum interference device flux qubit. The amplitude of the resonant peaks and dips are modulated by the power of the applied microwave irradiation and a population inversion is generated at low flux bias. These results, which can be addressed with Landau-Zener transition, are useful to develop an alternative means to initialize and manipulate the flux qubit, as well as to do a controllable population inversion used in a micromaser. © 2009 American Institute of Physics. ͓DOI: 10.1063/1.3093823͔As controllable artificial atoms, superconducting qubits have received considerable attention because of providing a new paradigm of quantum solid state physics. So far, many fantastic macroscopic quantum coherent phenomena 1,2 have been demonstrated in superconducting qubits. In addition, recent experiments show that the interaction between superconducting qubits and microwave ͑MW͒ resonant cavity can produce single photon, 2 which leads to a possible application of superconducting qubits as a micromaser. It is well known that population inversion, which maintains a majority of atoms in excited states rather than in ground state, has to be realized in order to ensure the amplification of the light and thus the laser process. Previous work 3,4 suggests that it is possible to generate population inversion in the superconducting quantum circuits subjected to MW radiation. In this letter, we report a further step in this direction: a controllable population inversion in a strongly driven radio frequency superconducting quantum interference device ͑rf-SQUID͒ by employing Landau-Zener ͑LZ͒ transition.LZ transition is a celebrated quantum mechanical phenomenon in the quantum world.5-7 It has been found in various physical systems, such as atoms in accelerating optical lattices, 8,9 superlattices, 10 nanomagnets, 11,12 quantum dots, 13 and Josephson junctions. [14][15][16] Recently LZ transition is also found in the superconducting qubits, [17][18][19][20] providing new insights into the fundamentals of quantum mechanics and holding promise for the superconducting qubits' application. One may use LZ to enhance the quantum tunneling rate, 21,22 prepare the quantum state, 23 control the qubit gate operations 13,24 effectively, and do the controllable population inversion as demonstrated in this letter.Our design of the superconducting flux qubit, being immune to charge noise and comparatively easy to be read out, is based on rf-SQUID. 25 An rf-SQUID consists of a superconducting loop with inductance L interrupted by one Josephson junction with capacitance C and critical current I c . Its dynamics can be described in terms of the variable ⌽ and are identical to those of a particle of "mass" C with kinetic energy C⌽ 2 / 2 moving in the potential U͑⌽͒. Herewhere ⌽ 0 is the flux quantum,close to one half of a flux quantum is applied, the potential ...

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“…Thus these low-lying energy eigenstates have a relatively small range of associated flux values and can therefore (at least for sufficiently small k) also be viewed as "fuzzy" eigenstates of the flux operator. By adjusting Φ ext , the energy levels are shifted, and for certain values of Φ ext , two levels in opposite wells can be made to align, which allows for resonant quantum tunneling between the wells (i.e., between two fluxoid states) [24,36], leading to a macroscopic change in the magnetic moment of the system.…”

Section: Squid Setup and Detection Of Superpositions Of Macroscopicalmentioning

confidence: 99%

Experimental motivation and empirical consistency in minimal no-collapse quantum mechanics

Schlosshauer

2006

Annals of Physics

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We analyze three important experimental domains (SQUIDs, molecular interferometry, and BoseEinstein condensation) as well as quantum-biophysical studies of the neuronal apparatus to argue that (i) the universal validity of unitary dynamics and the superposition principle has been confirmed far into the mesoscopic and macroscopic realm in all experiments conducted thus far; (ii) all observed "restrictions" can be correctly and completely accounted for by taking into account environmental decoherence effects; (iii) no positive experimental evidence exists for physical state-vector collapse; (iv) the perception of single "outcomes" is likely to be explainable through decoherence effects in the neuronal apparatus. We also discuss recent progress in the understanding of the emergence of quantum probabilities and the objectification of observables. We conclude that it is not only viable, but moreover compelling to regard a minimal no-collapse quantum theory as a leading candidate for a physically motivated and empirically consistent interpretation of quantum mechanics.

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Resonant macroscopic quantum tunneling in SQUID systems

Cited by 21 publications

References 18 publications

Strong Coupling Theory for Tunneling and Vibrational Relaxation in Driven Bistable Systems

Strong Coupling Theory for Tunneling and Vibrational Relaxation in Driven Bistable Systems

Population inversion induced by Landau–Zener transition in a strongly driven rf superconducting quantum interference device

Experimental motivation and empirical consistency in minimal no-collapse quantum mechanics

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