Department of Electrical Engineering and Computer Science, University of California, Berkeley, 94709, USA.
Phys Rev Lett. 2011 Jul 1;107(1):010604. doi: 10.1103/PhysRevLett.107.010604.
Nanomagnetic memory and logic circuits are attractive integrated platforms for studying the fundamental thermodynamic limits of computation. Using the stochastic Landau-Lifshitz-Gilbert equation, we show by direct calculation that the amount of energy dissipated during nanomagnet erasure approaches Landauer's thermodynamic limit of kTln(2) with high precision when the external magnetic fields are applied slowly. In addition, we find that nanomagnet systems behave according to generalized formulations of Landauer's principle that hold for small systems and generic logic operations. In all cases, the results are independent of the anisotropy energy of the nanomagnet. Lastly, we apply our computational approach to a nanomagnet majority logic gate, where we find that dissipationless, reversible computation can be achieved when the magnetic fields are applied in the appropriate order.
纳米磁性记忆和逻辑电路是研究计算基本热力学限制的有吸引力的集成平台。我们使用随机朗道-利夫希茨-吉尔伯特方程通过直接计算表明，当外部磁场缓慢施加时，纳米磁体擦除过程中耗散的能量接近拉兰德热力学极限 kTln(2)，精度非常高。此外，我们发现纳米磁体系统根据适用于小系统和通用逻辑操作的拉兰德原理的广义公式进行操作。在所有情况下，结果都与纳米磁体的各向异性能量无关。最后，我们将我们的计算方法应用于纳米磁体多数逻辑门，发现当磁场以适当的顺序施加时，可以实现无耗散、可逆的计算。
