Quantum Enabling System Technologies (QuEST) Group

Quantum optomechanics explores the interaction between radiation and mechanical degrees of freedom of a system by using quantum mechanical models of the electromagnetic field and the mechanical matter. It could play a significant role in future space missions such as using massive mechanical mirrors for high-mass matter-wave interferometry to test foundations of physics or for controlling quantum noise for gravitational wave detection. These are challenging to implement due to special requirements that should be met depending on the orbit, radiation, temperature gradients, mass and size restrictions, long-term stability, extreme forces during the launch phase, etc. A central problem in such space missions is efficient manipulation of heat transfer, in addition to receiving and rejecting heat. Another heat related major problem is to cool scientific instruments on board a spacecraft. This is achieved by either passively, using background thermal radiation in deep space, or actively, which is not preferred due to requirement of massive cryogenic components such as Helium tanks. Small, compact, and efficient cooling systems are highly sought for space applications. Existing studies are mainly instrument-specific and limited to classical models. Rapidly developing modern field of quantum thermodynamics promises quantum refrigerators with few qubits as well as highly efficient quantum heat transfer modules which can offer enabling technologies for space missions such as quantum-engineered functionalized interface surfaces and quantum heat machines.

Funding: EU-COST Action (CA15220) and TUBITAK (116F303)

Thermodynamics is the science of heat engines, or more fundamentally, science of energy, focusing on the interplay between heat and work. It is developed to deal with macroscopic systems, yet there is recent interest to built engines in microscopic limits. It is therefore necessary to examine thermodynamics in quantum regime. Exploration of quantum analogs of classical heat engines can be traced back to the recognition of maser as an Otto engine in 50s. Since then, quantum dots, trapped ions, spin systems, atomic condensates, optical cavities, quantum Hall systems, optomechanical resonators, and relativistic particles are considered as working substances for quantum heat engines (QHEs). Profound quantum effects emerge when quantum heat reservoirs are included. If quantum heat bath has quantum coherence, entanglement, or squeezing, QHE can surpass the Carnot bound. Observation of quantum advantages is challenged due to decoherence. However, quantum coherence is argued to survive in ambient temperatures in some biological processes, such as photosynthesis, being responsible for the ballistic transfer of energy. Information feedback from the environment could help to maintain coherence in these processes. Such an environment has a memory and called a non-Markovian reservoir. It is suggested for longevity of quantum memories, a crucial ingredient for quantum communication and quantum computation. Despite the analogies between QHEs and quantum information devices, there are only a few studies of non-Markovian reservoirs for QHEs. Our fundamental purpose is to establish mechanical equivalent of non-Markovian resources. Our practical purpose is to propose an optimum QHE that can use non-Markovian resources with capabilities surpassing classical counterparts.

Experimental evidences of long-lasting quantum coherence in the excitation energy transfer (EET) through photosynthetic pigment-protein complexes (such as FMO complex) have been reported since 2008 [1-4]. These observations together with the some other unexpected quantum coherence related observations (magneto-reception in birds and olfactory sense) in biological systems [5] led to a quest for novel theoretical explanations of these observations. It is argued that existence of quantum coherent superposition of excitons in the EET can bring an explanation [5] [6]. However, in large and noisy systems, coherence cannot live long. Yet this still can be explained by an interplay of non-Markovianity, open system quantum dynamics, and quantum coherence [7]. In our project, we are aiming to approach these observations in natural photosynthesis by realistic energy transfer models taking into account memory effects in the environment and quantum coherence; and then by following a bio-mimetic approach, we will propose efficient artificial photosynthesis systems. Intriguingly, our results could have broader scope as it is related to the interplay of quantum information and energy in non-Markovian open systems dynamics and could impact information storage and manipulation ways for quantum communication and computations.

References

• 1. G.S. Engel, et al., Nature 446, 2007 .
• 2. E. Collini, et al., Nature 463, 2010.
• 3. G. Panitchayangkoon, et al., PNAS, 2010.
• 4. G. Panitchayangkoon, et al., PNAS, 2011.
• 5. S.F. Huelga and M.B. Plenio, Contemporary Physics, 2013.
• 6. R.L. Purchase and H.J.M. de Groot, Rep. Prog. Phys., 2015.
• 7. A. W. Chin, et al., New J. Phys., 2010.

Our objective in this multinational project is to investigate if quantum physics can help to enhance the capabilities of energy storage and processing devices. We have recently reported that superradiance can be used as a “superwork” harvesting scheme that can lead to quadratic increase in the work output of a photonic Otto engine with the number of atoms powering the device [1]. We identified the physics behind the enhancement as a catalytic effect of quantum coherence. Our photonic quantum engine designs are inspired from light harvesting photosynthetic systems which can be relevant to “quantum photovoltaics” and “quantum biology” as well. In addition to photonic devices we consider atomic and molecular clusters, spin systems, including NMR, optomechanical and superconducting circuit QED systems for implementations of our ideas. We collaborate with Prof. Christopher Wilson group of IQC at University of Waterloo for experimental realizations. We have recently proposed a superconducting quantum piston engine [2]. This project is funded by a University Research Agreement between Koç University and Lockheed-Martin Chief Scientist’s Office.

We are also a member of atomQT action.

References

• 1. Superradiant Quantum Heat Engine, Ali Ü. C. Hardal and Özgür E. Müstecaplıoğlu: Sci Rep. 2015; 5: 12953. .
• 2. A Quantum Heat Engine with Coupled Superconducting Resonators, Ali Ü. C. Hardal, Nur Aslan, C. M. Wilson, Özgür E. Müstecaplıoğlu: Phys. Rev. E 96, 062120