Though they may not cut the mustard for a marriage proposal, flawed diamonds are ideal for maintaining quantum states. For the past few years scientists have found ways to influence and manipulate atoms near nitrogen-vacancy (NV) centers in flawed diamonds. These capabilities may someday make complex quantum computers or even a quantum internet a reality. 

So what exactly is quantum computing and how are quantum computers different than the run of the mill computers we already have? In a nutshell the difference lies in something called a quantum bit, or a qubit. A qubit is capable of maintaining a superposition of two states whereas classical bits are one state or the other, otherwise known as little ones and zeros. 

The key to understanding these processes lies in understanding the function of the NV center, one of the most common defects in diamond. As everyone knows a perfect diamond is made entirely of carbon; however, if nitrogen is introduced during formation it can become included as a defect.

Model of a Nitrogen Vacancy Center
Carbon alone would attach itself to 4 other carbon atoms; nitrogen however, bonds to only 3 carbon atoms creating the vacancy in the lattice structure where the 4th carbon atom would normally reside. This formation provides an electron free to move around the vacant space and around the neighboring atoms. The electron can then be coupled to the nuclear states of the surrounding carbon atoms and for the purpose of quantum computing they become entangled qubits. 

The problem with using the vacancy as a means for quantum computation is that it’s impractical to implant single nitrogen atoms one by one through a thin layer of diamond when you’d need several thousands in a single layer. In a study titled Chip-Scale Nanofabrication of Single Spins and Spin Arrays in Diamond, published in the July 23rd issue of Nano Letters, researchers described a method for mass-producing these NV centers, which may be fundamental in creating quantum networks. 

In the process researchers employed a thin layer of resist to cover the diamond. Through the resist they blast away using electron beam lithography. Next they shower the resist with nitrogen ions that end up going through the holes that were created in the top film layer. Once the nitrogen ions pass through the holes in the resist they embed themselves in the actual diamond creating the desired vacancies. Since the researchers were able to control the array of holes, they were able to control the array of vacancies. 

Thanks to these advancements it may now be possible to create vast networks of qubits, which someday may be lead to scalable quantum computers capable of complex problem solving. The next step to move forward in the quantum-computing race is for scientists to develop qubits that are able to hold their states for longer. This would provide processors with the means to run complex algorithms and perform practical problem solving. While diamonds are forever, unfortunately quantum states are not.