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Observation of non-Markovian micromechanical Brownian motion.

Gröblacher S, Trubarov A, Prigge N, Cole GD, Aspelmeyer M, Eisert J - Nat Commun (2015)

Bottom Line: The precise decoherence mechanisms, however, are often unknown for a given system.In sharp contrast to what is commonly assumed in high-temperature quantum Brownian motion describing the dynamics of the mechanical degree of freedom, based on a statistical analysis of the emitted light, it is shown that this spectral density is highly non-Ohmic, reflected by non-Markovian dynamics, which we quantify.We conclude by elaborating on further applications of opto-mechanical systems in open system identification.

View Article: PubMed Central - PubMed

Affiliation: 1] Kavli Institute of Nanoscience, Delft University of Technology, Delft 2628 CJ, The Netherlands [2] Vienna Center for Quantum Science and Technology (VCQ), Faculty of Physics, University of Vienna, Vienna A-1090, Austria.

ABSTRACT
All physical systems are to some extent open and interacting with their environment. This insight, basic as it may seem, gives rise to the necessity of protecting quantum systems from decoherence in quantum technologies and is at the heart of the emergence of classical properties in quantum physics. The precise decoherence mechanisms, however, are often unknown for a given system. In this work, we make use of an opto-mechanical resonator to obtain key information about spectral densities of its condensed-matter heat bath. In sharp contrast to what is commonly assumed in high-temperature quantum Brownian motion describing the dynamics of the mechanical degree of freedom, based on a statistical analysis of the emitted light, it is shown that this spectral density is highly non-Ohmic, reflected by non-Markovian dynamics, which we quantify. We conclude by elaborating on further applications of opto-mechanical systems in open system identification.

No MeSH data available.


Related in: MedlinePlus

Estimated coefficients.Depicted is the histogram of best estimated coefficients k in the local approximation within [ωmin, ωmax] of the spectral density by I(ω)=Cωk, showing a statistically significant deviation from the Ohmic situation of k=1.
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f3: Estimated coefficients.Depicted is the histogram of best estimated coefficients k in the local approximation within [ωmin, ωmax] of the spectral density by I(ω)=Cωk, showing a statistically significant deviation from the Ohmic situation of k=1.

Mentions: The main experimental result is shown in Fig. 3 (see also Supplementary Note 6). The histogram over all optimal power estimates yields k=−2.30±1.05, which is a clear deviation from k=1 for a locally Ohmic bath density, hence signifying a remarkably strong departure from Markovianity. It is well known that an Ohmic spectral density leads in the weak coupling and high-temperature regimes to Markovian dynamics1327. To further strengthen our analysis, we further make this link quantitative. We show that a deviation from a local Ohmic spectral density—which is precisely what is observed—leads to quantifiable non-Markovian dynamics.


Observation of non-Markovian micromechanical Brownian motion.

Gröblacher S, Trubarov A, Prigge N, Cole GD, Aspelmeyer M, Eisert J - Nat Commun (2015)

Estimated coefficients.Depicted is the histogram of best estimated coefficients k in the local approximation within [ωmin, ωmax] of the spectral density by I(ω)=Cωk, showing a statistically significant deviation from the Ohmic situation of k=1.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4525213&req=5

f3: Estimated coefficients.Depicted is the histogram of best estimated coefficients k in the local approximation within [ωmin, ωmax] of the spectral density by I(ω)=Cωk, showing a statistically significant deviation from the Ohmic situation of k=1.
Mentions: The main experimental result is shown in Fig. 3 (see also Supplementary Note 6). The histogram over all optimal power estimates yields k=−2.30±1.05, which is a clear deviation from k=1 for a locally Ohmic bath density, hence signifying a remarkably strong departure from Markovianity. It is well known that an Ohmic spectral density leads in the weak coupling and high-temperature regimes to Markovian dynamics1327. To further strengthen our analysis, we further make this link quantitative. We show that a deviation from a local Ohmic spectral density—which is precisely what is observed—leads to quantifiable non-Markovian dynamics.

Bottom Line: The precise decoherence mechanisms, however, are often unknown for a given system.In sharp contrast to what is commonly assumed in high-temperature quantum Brownian motion describing the dynamics of the mechanical degree of freedom, based on a statistical analysis of the emitted light, it is shown that this spectral density is highly non-Ohmic, reflected by non-Markovian dynamics, which we quantify.We conclude by elaborating on further applications of opto-mechanical systems in open system identification.

View Article: PubMed Central - PubMed

Affiliation: 1] Kavli Institute of Nanoscience, Delft University of Technology, Delft 2628 CJ, The Netherlands [2] Vienna Center for Quantum Science and Technology (VCQ), Faculty of Physics, University of Vienna, Vienna A-1090, Austria.

ABSTRACT
All physical systems are to some extent open and interacting with their environment. This insight, basic as it may seem, gives rise to the necessity of protecting quantum systems from decoherence in quantum technologies and is at the heart of the emergence of classical properties in quantum physics. The precise decoherence mechanisms, however, are often unknown for a given system. In this work, we make use of an opto-mechanical resonator to obtain key information about spectral densities of its condensed-matter heat bath. In sharp contrast to what is commonly assumed in high-temperature quantum Brownian motion describing the dynamics of the mechanical degree of freedom, based on a statistical analysis of the emitted light, it is shown that this spectral density is highly non-Ohmic, reflected by non-Markovian dynamics, which we quantify. We conclude by elaborating on further applications of opto-mechanical systems in open system identification.

No MeSH data available.


Related in: MedlinePlus