Quantum speed limits—primer, perspectives, and potential future directions

Frey, Michael

doi:10.1007/s11128-016-1405-x

Cited by 85 publications

(90 citation statements)

References 85 publications

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“…See [12] for a recent review of such quantum speed limits and their applications. Many estimates of computational capacity of physical systems have their starting point in the assumption that T −1 ⊥ * stephen.jordan@nist.gov can be interpreted as a maximum computational clock speed [11,[13][14][15][16][17][18][19][20][21][22][23][24][25].…”

Section: Introductionmentioning

confidence: 99%

Fast quantum computation at arbitrarily low energy

Jordan

2017

Phys. Rev. A

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One version of the energy-time uncertainty principle states that the minimum time T ⊥ for a quantum system to evolve from a given state to any orthogonal state is h/(4∆E) where ∆E is the energy uncertainty. A related bound called the Margolus-Levitin theorem states that T ⊥ ≥ h/(2 E ) where E is the expectation value of energy and the ground energy is taken to be zero. Many subsequent works have interpreted T ⊥ as defining a minimal time for an elementary computational operation and correspondingly a fundamental limit on clock speed determined by a system's energy. Here we present local time-independent Hamiltonians in which computational clock speed becomes arbitrarily large relative to E and ∆E as the number of computational steps goes to infinity. We argue that energy considerations alone are not sufficient to obtain an upper bound on computational speed, and that additional physical assumptions such as limits to information density and information transmission speed are necessary to obtain such a bound.

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Section: Introductionmentioning

confidence: 99%

Fast quantum computation at arbitrarily low energy

Jordan

2017

Phys. Rev. A

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“…The quantum speed limit (QSL) time of the closed system is defined as the minimal evolution time (corresponding to the maximal evolution velocity) from the initial state to its orthogonal state. A unified quantum speed limit time is given by the Mandelstan-Tamm (MT) bound and the Margolus-Levitin (ML) bound, i.e., τ qsl = max{π /(2∆E), π /(2 E )} [1][2][3][4][5][6][7][8][9][10][11]. The quantum speed limit is also related to other quantum information processing, such as the role of entanglement in QSL [12], the elementary derivation for passage time [13], the geometric QSL based on statistical distance [14,15], the quantum evolution control [16], the relationship among with coherence and asymmetry [17], and so on.…”

Section: Introductionmentioning

confidence: 99%

Quantum speed limit based on the bound of Bures angle

2020

Sci Rep

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In this paper, we investigate the unified bound of quantum speed limit time in open systems based on the modified Bures angle. This bound is applied to the damped Jaynes-Cummings model and the dephasing model, and the analytical quantum speed limit time is obtained for both models. As an example, the maximum coherent qubit state with white noise is chosen as the initial states for the damped Jaynes-Cummings model. It is found that the quantum speed limit time in both the non-Markovian and the Markovian regimes can be decreased by the white noise compared with the pure state. In addition, for the dephasing model, we find that the quantum speed limit time is not only related to the coherence of initial state and non-Markovianity, but also dependent on the population of initial excited state.

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“…While these approaches have often centered around non-interacting systems, STAs have also been explored in interacting, nonlinear, and other systems [20][21][22][23][24][25]. Remarkably, STAs have fundamental implications on quantum speed limits (QSL) [26][27][28][29][30], time-energy uncertainty relations (or energy cost) [31][32][33][34][35][36][37][38], and the quantification of the third law of thermodynamics in the context of quantum refrigerators [39,40], which results in intriguing practical applications in heat engines [41][42][43][44][45][46][47].…”

Section: Introductionmentioning

confidence: 99%

An efficient nonlinear Feshbach engine

Fogarty

Campbell

et al. 2018

New J. Phys.

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We investigate a thermodynamic cycle using a Bose-Einstein condensate (BEC) with nonlinear interactions as the working medium. Exploiting Feshbach resonances to change the interaction strength of the BEC allows us to produce work by expanding and compressing the gas. To ensure a large power output from this engine these strokes must be performed on a short timescale, however such non-adiabatic strokes can create irreversible work which degrades the engine's efficiency. To combat this, we design a shortcut to adiabaticity which can achieve an adiabatic-like evolution within a finite time, therefore significantly reducing the out-of-equilibrium excitations in the BEC. We investigate the effect of the shortcut to adiabaticity on the efficiency and power output of the engine and show that the tunable nonlinearity strength, modulated by Feshbach resonances, serves as a useful tool to enhance the system's performance.

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Quantum speed limits—primer, perspectives, and potential future directions

Cited by 85 publications

References 85 publications

Fast quantum computation at arbitrarily low energy

Fast quantum computation at arbitrarily low energy

Quantum speed limit based on the bound of Bures angle

An efficient nonlinear Feshbach engine

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