IBM Q Experience as a versatile experimental testbed for simulating open quantum systems

Guillermo García-Pérez,Sabrina Maniscalco,Matteo A C Rossi

doi:10.1038/s41534-019-0235-y

Guillermo García-Pérez, Sabrina Maniscalco + Show 1 more

Open Access

https://doi.org/10.1038/s41534-019-0235-y

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Abstract

The advent of noisy intermediate-scale quantum (NISQ) technology is changing rapidly the landscape and modality of research in quantum physics. NISQ devices, such as the IBM Q Experience, have very recently proven their capability as experimental platforms accessible to everyone around the globe. Until now, IBM Q Experience processors have mostly been used for quantum computation and simulation of closed systems. Here, we show that these devices are also able to implement a great variety of paradigmatic open quantum systems models, hence providing a robust and flexible testbed for open quantum systems theory. During the last decade an increasing number of experiments have successfully tackled the task of simulating open quantum systems in different platforms, from linear optics to trapped ions, from nuclear magnetic resonance (NMR) to cavity quantum electrodynamics. Generally, each individual experiment demonstrates a specific open quantum system model, or at most a specific class. Our main result is to prove the great versatility of the IBM Q Experience processors. Indeed, we experimentally implement one and two-qubit open quantum systems, both unital and non-unital dynamics, Markovian and non-Markovian evolutions. Moreover, we realise proof-of-principle reservoir engineering for entangled state generation, demonstrate collisional models, and verify revivals of quantum channel capacity and extractable work, caused by memory effects. All these results are obtained using IBM Q Experience processors publicly available and remotely accessible online.

Highlights

The theory of open quantum systems studies the dynamics of quantum systems interacting with their surroundings.[1,2,3] In its most general formulation, it allows us to describe the out-of-equilibrium properties of quantum systems, it provides a theoretical framework to assess the quantum measurement problem, and it gives us the tools to investigate, understand and counter the deleterious effects of noise on quantum technologies
The results presented in the previous section highlight how fewqubit noisy intermediate-scale quantum (NISQ) devices publicly available on the cloud already provide sufficient robustness and reliability to implement experimentally a number of open quantum systems dynamics, both Markovian and non-Markovian, both unital and non-unital
We have simulated all the paradigmatic open quantum systems models typically used to demonstrate physical phenomena induced by the presence of the environment, its consequences for quantum technological applications, and possible benefits in the spirit of reservoir engineering

Summary

INTRODUCTION

The theory of open quantum systems studies the dynamics of quantum systems interacting with their surroundings.[1,2,3] In its most general formulation, it allows us to describe the out-of-equilibrium properties of quantum systems, it provides a theoretical framework to assess the quantum measurement problem, and it gives us the tools to investigate, understand and counter the deleterious effects of noise on quantum technologies. Known as the Born–Markov approximation, one can derive a general equation in the so called Lindblad form, able to describe the physical evolution of quantum states.[1,2,3,4,5] When these assumptions are not satisfied, e.g., for strong system–environment interaction and/ or long-living environmental correlations, we enter the intricate (and somewhat fuzzy) reign of non-Markovian dynamics This consideration already illustrates how, despite its indubitable foundational nature, open quantum systems theory is still far from being completely understood and, it is peppered with unanswered questions of deep nature. Our results clearly prove that even small quantum processors are versatile and robust testbeds for verifying a number of theoretical open quantum systems results and predictions, paving the way to both new discoveries and a deeper understanding of one of the most fascinating and fundamental fields of quantum physics

RESULTS

García-Pérez et al 3

DISCUSSION

METHODS