Palak AroraCSE DepartmentIIIT Naya Raipur Chhattisgarh, IndiaEnrollment no:16101036Email: [email protected] Shipra KanaujiaCSE DepartmentIIIT Naya Raipur Chhattisgarh , IndiaEnrollment no. : 16100053Email: [email protected]

edu.in Abstract— The idea behind quantum computing is to resolveproblems in various domains of mathematics, physics, chemistry etc. They aremainly deployed to perform operations that are super complex in nature and arebeyond the computing of conventional computers. They basically work with thetechnology of qubits in which the control signals are operated upon. The qubitsare represented using Bloch sphere, in which any point denotes a combination ofqubits. The functionality of qubits depends upon two states spin-up andspin-down. These states are govern by RF techniques and control signals. IBMhas recently announced a quantum computer with the capability of 50 qubits(quantum bits).

This breakthrough has made IBM iconic in the field of quantum computing, as this has been the largest quantum computing system ever physicallypossible. Keywords: Moore’s law,Shor’s algorithm, qubit, Grover’s algorithm .I. INTRODUCTION Beforementioning the facts and figures of quantum computing, we should drill the needof quantum computing and what does it serve even when the conventionalcomputing methods have made their impacts at profound scale.

The conventional computingmethodologies involve the usage of transistors for storing data in binary formsi.e. 0’s and1’s and process this data. In 1960’s , Intel co-founder GordonMoore perceived that the power ofcomputers doubles roughly eighteen months and this is known as Moore’s Law.

Thecomputing problems require more storage as more information needs to be stored.Quantum computing is solely based upon quantum theory which deals with theatoms and the smaller particles in them.Quantumcomputers work on qubits which are represented as points on sphere i.e.

0and 1are represented as north and south pole respectively, any point on the sphereis a reasonable qubit state which is a combination of 0 and 1 and algorithms such as Shor’salgorithm and Grover’s algorithm have proved to be computing at an enormousspeed with quantum computers but it is not necessarily true that quantumcomputers are superiors to the conventional computers. II. WORKING I. TECHNOLOGY USED· CouplingMechanism: In conventional computersbits propagate via bus which is a combination of wires and each wire carriesone bit and are transferred between memory and processor and vice-versa. Inquantum computers qubits stay at the memory location itself and control signalsare operated on them to implement logical operations which include at least twoqubits simultaneously. · Interfacingbits with Chip: The qubits are fed to anharmonicoscillator which is made by a capacitor and a non-linear inductor provided by Josephson’sjunction formed of two pieces of aluminum. These junctions are placed inparallel. Qubits are integrated together and passed on two superconducting resonatorsmade of niobium alloys.

These qubits use electron spin–up and spin –downstates as 0 &1 in a magnetic field. There are two types of qubits electronicspin & superconducting which rely on control signals (analog) and use RF techniques. These two methods areapproximately similar. II. OPERATIONON SPIN QUBITS Quantumdots have discrete energy levels for the two states up and down. Quantum dots are coupled to a pool having Efas the Fermi- level, under applied voltage the dot levels are pushed above the Fermilevels and then brought down so that only the spin-up state can be filled andthen again pushed fully down. Typical voltage pulse is in the 10mV range. Single spin control: The bits can be flipped by applying a microwave excitation to the corresponding dot which rotates the spin.

This operation corresponds to 180 degree rotation of the state in the sphere. The axis of rotation is determined by the phase of the microwave field. 2 Qubit Gate synchronization:The gate voltage pulses flips the middle spin which is conditionally dependent on the state of left spin constituting of a two qubit gate then the voltagepulse is removed. Reading Output Criteria: A spin-up electron stays in the dot because it doesn’t poses the required energy to reach the vacant states in the pool whereas the spin-down electron moves out of the pool getting replaced by a spin-up electron. The current measurement in this area will reveal the spin state. III.

PROGRAMMINGOF QUANTUM COMPUTERSItis similar to conventional computers which requires a programming language, interpreters,set of instructions and a defined architecture. The instructions deployed arethen transferred via control signals and then operated on the qubits. To get anidea about the number of qubits only 50 qubits’ states are stored (whichrequire memory larger than the largest supercomputers at present. Algorithm: IV.

ERROR CORRECTION TECHNIQUESOne ofthe mainly faced errors while performing operations through quantum computersis decoherence i.e. qubit states change over time due to the interactions withinenvironments to vanquish this error various techniques are applied in which theerror probability per operation must be less than the tolerance threshold butit is an expensive procedure and thus, an important area of research. V. SUBSEQUENTCHALLENGESQubitsthat are currently being integrated and operated on a chip are dependent uponheavy and costly equipment.

These qubits require calibration at every niche oftime thus calibrating millions of these needs major developments in this field.There is a need to increase the number of qubits. Initializing qubits toarbitrary and values reading the values stored in them easily. Atpresent millions of transistors are integrated in a microprocessor but most ofthem are connected to each other on the chip itself thus the number of pins ina package increase .In quantum computing every qubit requires a control signalthat is to operate upon the qubit, so multiplexing of qubits and control signalis essential but this found practical in real environments. VI. CONCLUSIONVariousglobal companies such as IBM, INTEL, and MICROSOFT etc.

have alreadyestablished research programs in this arena. Through these collaborations we foreseea large scale quantum computer in the future but it is also doubtful thatintegration of such a huge technology will be commercially viable for thevarious domains and personal usage and the integration of massive number ofqubits will be able to solve appropriate problems in the future. REFERENCESWhile implementingthis idea and writing the report we have taken help from Journal/conferencepapers, books, website, web article, newspaper, please refereed here one by oneas follows: 1 http://ieeexplore.ieee.org/document/7870244/2 https://futurism.com/ibm-announced-50-qubit-quantum-computer/3 https://en.wikipedia.org/wiki/Quantum_computing#cite_note-107