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We use time-resolved Faraday rotation to measure coherent spin dynamics in colloidal CdSe quantum dots charged in an electrochemical cell at room temperature. Filling of the 1Se electron level is demonstrated by the bleaching of the…

Other Condensed Matter · Physics 2007-05-23 N. P. Stern , M. Poggio , M. H. Bartl , E. L. Hu , G. D. Stucky , D. D. Awschalom

We employ two-dimensional (2D) coherent, nonlinear spectroscopy to investigate couplings within individual InAs quantum dots (QD) and QD molecules. Swapping pulse ordering in a two-beam sequence permits to distinguish between rephasing and…

Radiation sensors based on the heating effect of the absorbed radiation are typically relatively simple to operate and flexible in terms of the input frequency. Consequently, they are widely applied, for example, in gas detection, security,…

Mesoscale and Nanoscale Physics · Physics 2020-10-02 R. Kokkoniemi , J. -P. Girard , D. Hazra , A. Laitinen , J. Govenius , R. E. Lake , I. Sallinen , V. Vesterinen , P. Hakonen , M. Möttönen

Coupling to phonon modes is a primary mechanism of excitonic dephasing and energy loss in semiconductors. However, low-energy phonons in colloidal quantum dots and their coupling to excitons are poorly understood, since their experimental…

Mesoscale and Nanoscale Physics · Physics 2019-10-22 Albert Liu , Diogo B. Almeida , Wan-Ki Bae , Lazaro A. Padilha , Steven T. Cundiff

We study the leakage dynamics of charge stored in an ensemble of CdTe quantum dots embedded in a field-effect structure. Optically excited electrons are stored and read out by a proper time sequence of bias pulses. We monitor the dynamics…

Cross-correlation heterodyne detectors exhibit the potential for suppression of the detection quantum noise below shot noise without use of optical squeezing for capturing weak optical signals in low frequency bands. To understand the…

Quantum Physics · Physics 2022-11-09 Sheng Feng , Kaikai Wu

In this paper, we carry out a theoretical analysis of the zero-frequency and finite-frequency shot noise in electron tunneling through a two-level interacting system connected to two leads, when a coherent coupling between the two levels is…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 Ivana Djuric , Bing Dong , H. L. Cui

Characterizing charge noise is of prime importance to the semiconductor spin qubit community. We analyze the echo amplitude data from a recent experiment [Yoneda et al., Nat. Nanotechnol. 13, 102 (2018)] and note that the data shows small…

Mesoscale and Nanoscale Physics · Physics 2019-02-22 Utkan Güngördü , J. P. Kestner

We present the experimental realization of a Quantum Dot (QD) operating as a high-frequency noise detector. Current fluctuations produced in a nearby Quantum Point Contact (QPC) ionize the QD and induce transport through excited states. The…

Mesoscale and Nanoscale Physics · Physics 2009-11-11 E. Onac , F. Balestro , L. H. Willems van Beveren , U. Hartmann , Y. V. Nazarov , L. P. Kouwenhoven

We present a method to determine the shot noise in quantum systems from knowledge of their time evolution - the latter being obtained using numerical simulation techniques. While our ultimate goal is the study of interacting systems, the…

Mesoscale and Nanoscale Physics · Physics 2015-05-18 A. Branschädel , E. Boulat , H. Saleur , P. Schmitteckert

Multidimensional coherent optical spectroscopy is one of the most powerful tools for investigating complex quantum mechanical systems. While it was conceived decades ago in magnetic resonance spectroscopy using micro- and radio-waves, it…

Critical points and phase transitions are characterized by diverging susceptibilities, reflecting the tendency of the system toward spontaneous symmetry breaking. Equilibrium statistical mechanics bounds these instabilities to occur at zero…

Mesoscale and Nanoscale Physics · Physics 2019-06-03 Orazio Scarlatella , Rosario Fazio , Marco Schiró

Precision spectroscopy of solid-state systems is challenging due to inhomogeneous broadening. We describe a technique -- coherent quantum beats -- that enables the measurement of small frequency shifts within an inhomogeneously broadened…

Atomic Physics · Physics 2023-07-04 Harish D. Ramachandran , Julia E. Ford , Amar C. Vutha

Here we report on fabrication and low temperature magnetotransport measurements of quantum point contacts patterned from a novel two-dimensional electron system - CdTe/CdMgTe modulation doped heterostructure. From the temperature and bias…

Mesoscale and Nanoscale Physics · Physics 2013-05-30 M. Czapkiewicz , V. Kolkovsky , P. Nowicki , M. Wiater , T. Wojciechowski , T. Wojtowicz , J. Wróbel

A double quantum dot device is a tunable two-level system for electronic energy states. A dc electron current directly measures the rates for elastic and inelastic transitions between the two levels. For inelastic transitions energy is…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 T. Fujisawa , T. H. Oosterkamp , W. G. van der Wiel , B. W. Broer , R. Aguado , S. Tarucha , L. P. Kouwenhoven

Electron spins in silicon have long coherence times and are a promising qubit platform. However, electric field noise in semiconductors poses a challenge for most single- and multi-qubit operations in quantum-dot spin qubits. Here, we…

Mesoscale and Nanoscale Physics · Physics 2020-07-27 Elliot J. Connors , JJ Nelson , Haifeng Qiao , Lisa F. Edge , John M. Nichol

We carry out a detailed analysis of coherent resonant tunneling through two coupled quantum dots (CQD) in a parallel arrangement in the weak tunneling limit. We establish a set of quantum rate equations (QREs) in terms of the…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 Bing Dong , X. L. Lei , N. J. M. Horing

Measuring the power spectral density of a stochastic process, such as a stochastic force or magnetic field, is a fundamental task in many sensing applications. Quantum noise is becoming a major limiting factor to such a task in future…

Genuine quantum-mechanical effects are readily observable in modern optomechanical systems comprising bosonic ("classical") optical resonators. Here we describe unique features and advantages of optical two-level systems, or qubits, for…

Using micro- and nano-scale resonantly excited PL and PLE, we study the excitonic structure of CdSe/ZnSe and CdTe/ZnTe self assembled quantum dots (SAQD). Strong resonantly enhanced PL is seen at one to four optic phonon energies below the…