Consistent Treatment of Spin-Selective Recombination of a Radical Pair Confirms the Haberkorn Approach

Ivanov, Konstantin L.; Петрова, М. В.; Lukzen, Nikita N.; Maeda, Kiminori

doi:10.1021/jp1048265

Cited by 66 publications

(75 citation statements)

References 25 publications

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“…(4) was originally introduced on a phenomenological basis, it can be shown that incoherent spindependent reactions by interactions with a thermal bath are taken into account correctly by the anticommutator of and ρ. 16 ρ in Eq. (4) is strictly speaking no density matrix, as the trace of the matrix is not equal to one.…”

Section: Stochastic Liouville Equationmentioning

confidence: 99%

Microscopic modeling of magnetic-field effects on charge transport in organic semiconductors

et al. 2011

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The stochastic Liouville equation is applied to the field of organic magnetoresistance to perform detailed microscopic calculations on the different proposed models. By adapting this equation, the influence of a magnetic field on the current in bipolaron, electron-hole pair, and triplet models is calculated. The simplicity and wide applicability of the stochastic Liouville equation makes it a powerful tool for interpreting experimental results on magnetoresistance measurements in organic semiconductors. New insights are gained on the influence of hopping rates and disorder on the magnetoresistance.

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Section: Stochastic Liouville Equationmentioning

confidence: 99%

Microscopic modeling of magnetic-field effects on charge transport in organic semiconductors

et al. 2011

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“…Although other treatments are possible [27,28], here we follow the Haberkorn approach as it is the most consistent for the spin-selective recombination of radicals [29]. We begin the evolution at the moment of radical pair creation with the initial density matrix…”

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confidence: 99%

Quantum Coherence and Sensitivity of Avian Magnetoreception

Bandyopadhyay¹,

Paterek²,

Kaszlikowski³

2012

Phys. Rev. Lett.

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Migratory birds and other species have the ability to navigate by sensing the geomagnetic field. Recent experiments indicate that the essential process in the navigation takes place in bird's eye and uses chemical reaction involving molecular ions with unpaired electron spins (radical pair). Sensing is achieved via geomagnetic-dependent dynamics of the spins of the unpaired electrons. Here we utilize the results of two behavioral experiments conducted on European Robins to argue that the average life-time of the radical pair is of the order of a microsecond and therefore agrees with experimental estimations of this parameter for cryptochrome -a pigment believed to form the radical pairs. We also found a reasonable parameter regime where sensitivity of the avian compass is enhanced by environmental noise, showing that long coherence time is not required for navigation and may even spoil it.PACS numbers: 03.65.Yz, Recently there has been a growing interest in the application of quantum mechanics to understand many biological phenomena such as photosynthesis [1][2][3][4][5][6][7], process of olfaction [8,9], enzymatic reactions [10,11] or avian magnetoreception [12][13][14][15]. These interests have brought physicists, chemists, and biologists at the same platform and led to the beginning of a new interdisciplinary subject called quantum biology [16,17]. A major motivation of these studies is to understand how nature utilizes purely quantum phenomena to optimize various biological processes.Here we are specifically interested in the avian magnetoreception. It is very plausible that the navigation ability of some migratory birds is governed by the mechanism based on geomagnetic-dependent dynamics of spins of unpaired electrons in a radical pair. A recent theoretical study has estimated both the life-time of the pair and the coherence time of this dynamics to be of the order of tens of microsecond [15]. The basic criterion used there postulates that bird's navigation is disturbed if the signal produced by the dynamics is independent of the orientation of the geomagnetic field. This criterion together with the results of behavioral experiments in which European Robins could not navigate in a weak oscillating magnetic field [18,19] led to the estimated life time and coherence time. Here we additionally take into account the results of other behavioral experiments in which the same species were observed to be temporarily disoriented in a constant magnetic field sufficiently stronger or weaker than the geomagnetic field [20,21]. We estimate the life time and coherence time of the order of several microseconds. Our estimate is consistent with that obtained in a recent behavioral experiment [13] and also with the in vitro experiment using cryptochrome [22], a pigment believed to form the radical pairs. Furthermore, we demonstrate theoretically that environmental noise can enhance * jnbandyo@gmail.com the sensitivity of the avian compass, i.e. sensitivity in the presence of noise is better than without noise. This increase ...

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“…We suppose that the only magnetic interactions are the Zeeman interactions of the two electrons, and in order to induce S-T mixing, we consider the ∆g mechanism [10] and the Kominis theory [11]. The full master equation of the traditional theory [37,38] leads to the same result as in case (a). In the right yaxis of (c) we plot the normalization of ρ, in order to elucidate the fact that there still exists a substantial number of radialion pairs at the time when the predictions of the two theories (Jones-Hore and Kominis) start to significantly deviate from the third (traditional).…”

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confidence: 99%

Magnetic sensitivity and entanglement dynamics of the chemical compass

Kominis

2012

Chemical Physics Letters

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We present the quantum limits to the magnetic sensitivity of a new kind of magnetometer based on biochemical reactions. Radical-ion-pair reactions, the biochemical system underlying the chemical compass, are shown to offer a new and unique physical realization of a magnetic field sensor competitive to modern atomic or condensed matter magnetometers. We elaborate on the quantum coherence and entanglement dynamics of this sensor, showing that they provide the physical basis for testing our understanding of the fundamental quantum dynamics of radical-ion-pair reactions.Quantum physics, in particular quantum information, control and measurement are concepts rapidly infiltrating biological or biochemical processes. For example, quantum coherence has been shown to play a fundamental role in photosynthesis [1][2][3][4][5][6][7][8], while quantum measurement dynamics have been demonstrated to underlie radical-ionpair reactions [9][10][11], the spin-dependent biochemical reactions at the heart of the avian magnetic compass mechanism. Even electron spin entanglement has also been addressed with respect to the chemical compass [12,13], paving the way for the dawn of quantum biology [14].We will here show that spin-selective radical-ion-pair reactions are no different than atomic [15] or solid state quantum sensors [16] used in e.g. precision metrology [17][18][19], and in principle are able to offer an exquisite magnetic sensitivity. We will establish the fundamental quantum limits to the magnetic sensitivity of these biochemical sensors, and we will elaborate on the fundamental decoherence mechanism present. We will show that the mechanism damping singlet-triplet coherence also damps any electron spin entanglement possibly present, as is well understood in precision measurements. In so doing, we will also show that the recently appeared entanglement considerations [12,13] are questionable, since these works have not taken into account the fundamental singlet-triplet decoherence process. Finally, we will compare the three different and currently competing master equations attempting to describe the quantum dynamics of radical-ion-pair reactions. Based on their ability to correctly account for the coherence and entanglement dynamics of these reactions, it will be shown that one out of the three theories can be eliminated.Radical-ion pairs (Fig. 1) [20][21][22] are biomolecular ions with two unpaired electrons and any number of magnetic nuclei, created by a charge transfer from a photo-excited D * A donor-acceptor molecular dyad DA. The magnetic nuclei of the donor and acceptor molecules couple to the two electrons via the hyperfine interaction, leading to singlet-triplet (S-T) mixing, i.e. a coherent oscillation of the total electron spin state, also affected by the electrons' Zeeman interaction with the external magnetic field. Singlet-triplet coherence (and its relaxation) is studied in a variety of contexts, as e.g. in NMR [23][24][25] and quantum dots [26][27][28]. The additional complication of radical-ion-pair reactio...

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Consistent Treatment of Spin-Selective Recombination of a Radical Pair Confirms the Haberkorn Approach

Cited by 66 publications

References 25 publications

Microscopic modeling of magnetic-field effects on charge transport in organic semiconductors

Microscopic modeling of magnetic-field effects on charge transport in organic semiconductors

Quantum Coherence and Sensitivity of Avian Magnetoreception

Magnetic sensitivity and entanglement dynamics of the chemical compass

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