Generation of superposition states and charge-qubit relaxation probing in a circuit

Neto, O. P. de Sá; Oliveira, M. C. de; Caldeira, A. O.

doi:10.1088/0953-4075/44/13/135503

Cited by 5 publications

(9 citation statements)

References 26 publications

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“…Specifically, we focused on fullerene molecules and observed that when the time scales of decoherence and dissipation are close and dependent on the propagation time during which the system is coupled to the environment, the inclusion of dissipation becomes necessary. The combined effect of decoherence and dissipation leads to a more significant degradation of quantum behavior compared to pure decoherence, providing further insights for understanding other systems [14,36,37].…”

Section: Discussionmentioning

confidence: 99%

Open quantum behaviour manifested in the double-slit experiment

Marinho,

de Sá Neto,

Sampaio

et al. 2023

EPL

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In certain analyses of quantum systems, it is common to disregard the dissipation eﬀect and focus solely on decoherence. This is because decoherence typically occurs on a much shorter timescale compared to dissipation. However, in order to gain insight into the role of dissipation, we examine the interference pattern in a double-slit experiment while considering both eﬀects. To do so, we establish time scales for decoherence and dissipation and acknowledge the possibility of these eﬀects occurring in close proximity. By comparing the relative intensity and fringe visibility between a purely decoherent model and a model that incorporates both decoherence and dissipation, we make an observation. When the time scales of decoherence and dissipation are similar, there exists a time interval during propagation where dissipation contributes to the faster degradation of quantum features compared to the sole inﬂuence of decoherence. Hence, it is crucial to consider both decoherence and dissipation eﬀects, especially when their time scales are closely aligned, to gain a comprehensive understanding of quantum behavior.

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Section: Discussionmentioning

confidence: 99%

Open quantum behaviour manifested in the double-slit experiment

Marinho,

de Sá Neto,

Sampaio

et al. 2023

EPL

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“…The more relevant dissipative effect comes in fact from the superconducting charge qubit decayng time [39] (see [5] for a compreensive review of some recent experimental numbers). At the frequencies of GHz necessary for the present porposal the charge qubit decay will affect the squeezing of the TLR 2 field, and therefore will affect the accuracy of the detection process.…”

Section: Discussionmentioning

confidence: 99%

Temperature measurement and phonon number statistics of a nanoelectromechanical resonator

2015

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Measuring thermodynamic quantities can be easy or not, depending on the system that is being studied. For a macroscopic object, measuring temperatures can be as simple as measuring how much a column of mercury rises when in contact with the object. At the small scale of quantum electromechanical systems, such simple methods are not available and invariably detection processes disturb the system state. Here we propose a method for measuring the temperature on a suspended semiconductor membrane clamped at both ends. In this method, the membrane is mediating a capacitive coupling between two transmission line resonators (TLR). The first TLR has a strong dispersion, that is, its decaying rate is larger than its drive, and its role is to pump in a pulsed way the interaction between the membrane and the second TLR. By averaging the pulsed measurements of the quadrature of the second TLR we show how the temperature of the membrane can be determined. Moreover the statistical description of the state of the membrane, which is directly accessed in this approach is significantly improved by the addition of a Josephson junction coupled to the second TLR.

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“…Those states have been historically proved to be hard to generate [4,24], but in principle they could be easily engineered in microwave fields in coplanar transmission lines, as has been demonstrated recently [25]. Previously, in [16] we demonstrated an alternative proposal to generate a superposition of coherent states of a microwave field in a transmission line resonator through interaction with a single superconducting charge qubit controlled by an external single classical magnetic pulse. By assuming a continuously varying magnetic pulse the generation can almost be deterministic.…”

Section: Introductionmentioning

confidence: 94%

“…For a 'fast' pulse x (t ) (a pulse with a duration equal or shorter than the half-period of oscillations) (see [16]), and when the 'artificial atom' and central line resonator field are prepared in an initial state |0 |α at t 0 = 0, the first-order terms in equation ( 6) are negligible and we can consider only terms of second order. So the temporal evolution…”

Section: Time-dependent State Dynamicsmentioning

confidence: 99%

“…This feature makes this system quite attractive for quantum information processing [8,9], and many proposals have been addressed recently (see e.g. [10][11][12][13][14][15][16][17][18][19] and references therein). The circuit corresponding to equation ( 1) is schematized in figure 1, where a central resonator transmission line is capacitively coupled to a charged qubit.…”

Section: Introductionmentioning

confidence: 99%

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Quantum bit encoding and information processing with field superposition states in a circuit

Neto

Oliveira

2012

J. Phys. B: At. Mol. Opt. Phys.

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Solid-state superconducting devices coupled to coplanar transmission lines offer an exquisite architecture for quantum optical phenomena probing as well as for quantum computation implementation, which is the object of intense theoretical and experimental investigation lately. Under appropriate conditions, the transmission line radiation modes can become strongly coupled to a superconducting device with only two levels—for that reason called an artificial atom or qubit. Employing this system, we propose a two-quantum bit gate encoding, involving quantum electromagnetic field qubit states prepared in a coplanar transmission line capacitively coupled to a single charge qubit. Since dissipative effects are more drastic in the solid-state qubit than in the field one, it can be employed for the storage of information, whose efficiency against the action of an ohmic bath shows that this encoding can be readily implemented with present-day technology. We extend the investigation to generate entanglement between several solid-state qubits and the field qubit through the action of external classical magnetic pulses.

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Generation of superposition states and charge-qubit relaxation probing in a circuit

Cited by 5 publications

References 26 publications

Open quantum behaviour manifested in the double-slit experiment

Open quantum behaviour manifested in the double-slit experiment

Temperature measurement and phonon number statistics of a nanoelectromechanical resonator

Quantum bit encoding and information processing with field superposition states in a circuit

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